We shall now make a rapid tour of the English and Welsh coasts, most regretfully omitting those of Scotland. The deep indentations of the Scottish coastline give it a length out of all proportion to the size of the country and a description of it, even in bare outline, is outside the scope of this article. This is all the more to be deplored, because so much of the coast of Scotland is unsurpassed in grandeur and charm. It most certainly deserves an article to itself.
Let us start at Berwick-on-Tweed and make our way down the east coast of England, along the south coast to Land’s End and up the west coast to the Solway Firth, pausing here and there to look more closely at the beaches which bear pebbles of unusual interest and hastening along those of little merit.
A pebble connoisseur, who roamed the English beaches over a century ago in search of semi-precious and fossiliferous stones, made this pronouncement: ‘Mediocrity in pebbles is insufferable.’ We do not go so far as that. Every pebble is of some interest, but there are a few beaches where the pebbles are so uniform in nature as to damp the ardour of the most fervent collector. These we will pass over rapidly. (A) THE EAST COAST : BERWICK-ON-TWEED TO DOVER The Northumberland coast has much to offer the student of pebbles and also gives him a pleasant setting for the pursuit of his hobby. Its attractiveness lies in its long, sandy bays, Holy Island, the Fame Islands archipelago, and the expansive sand-dunes in the bays north of Dunstanburgh Castle.
The prevailing rocks in the low-lying land behind the beaches are shale and limestone and they, of course, have made a large contribution to the shingle, but other sources have added their quota and, together, they make up an inviting miscellany. All this region received a thick covering of glacial drift during the Ice Age and there are few parts of its coast where layers of boulder clay are not exposed. The shingle, in consequence, contains innumerable pebbles that have made long, glacier-borne journeys, many of them from the distant north and all of them setting you a pretty little problem as to their origin and content. Then, again, the river Tweed, fed by tributaries from the hills of southern Scotland, has rolled down to its estuary at Berwick the pebbles it has shaped during its long, meandering course. The longshore drifting from north to south has brought many of them to the Northumbrian beaches. It has also brought pebbles from the coast of Berwickshire, products of the fine-grained red volcanic rocks that form the impressive St. Abb’s Head and of the medley of igneous and sedimentary cliffs still farther north. Another most interesting source of the shingle is a formation of rock known to geologists as the Great Whin Sill. A sill is an intrusive sheet of igneous rock between the layers (or bedding-planes) of older rocks. At the time of the intrusion the invading rock must have been in a liquid or semi-liquid state and, as it slowly cooled and solidified, it took the shape of the space into which it had obtruded itself. We have used the word ‘sheet’, which suggests a layer of extreme thinness, but the Great Whin Sill has an average thickness of 100 feet. However, even this is thin enough in comparison with the length and breadth of the sill, for it has pushed its way into five counties: Northumberland, Durham, Yorkshire, Cumberland and Westmorland, its penetrations covering an area of 1,500 square miles. The rock is hard and durable, standing out here and there in ridges above the softer sedimentary rocks which have been less able to resist denudation. One of these ridges is the long one on which the Roman Hadrian built his wall. Another gives a firm foundation to the walls of Bamburgh and Dunstanburgh castles. The Fame Islands are made of it. It comes out on the coast at Budle Point and in the Harkness Rocks, east of Bamburgh Castle, then almost disappears, appearing prominently again in the form of a fairly high cliff at Dunstanburgh and running thence all the way to Cullernose Point. Here you will notice clearly the columnar formation of the Whin rock. The columns are much less regular in shape than the hexagonal columns of basalt on the Isle of Staffa. Most of them are very roughly pentagonal (five-sided). The Whin Sill rock cooled too slowly to become basalt. It can be more correctly termed dolerite. Whinstone pebbles deserve a place in your collection. Break one of them and examine the surface of the fresh fracture. Its colour, in most instances, is a dark greyish-blue. Its crystals are smaller than those of granite, which took longer to cool.
The only trace of the Whinstone on Holy Island (Lindisfarne) is the piece of rock on which the castle stands. The rest of the island is of sedimentary rock, most of it sandstone. You will find many sandstone pebbles among the shingle of the island; intermingled with them are some pebbles of the boulder clay in which this coast abounds.
Proceeding southwards from Cullernose Point, we pass along a coast of shale, sandstone and grit. Millstone grit is the predominant rock for most of the way to Alnmouth and beyond that estuary to the mouth of the river Coquet. The shingle spits on the northern side of each of these estuaries clearly show that the longshore drift of pebbles all along this coast is from north to south. In each case the accumulation of the southward drifting shingle has prevented the river from entering the sea at a more northerly point. The shingle consists of grit and sandstone pebbles, together with the many varieties of ice-borne pebbles eroded from the boulder clay. It may save wearisome repetition if we state here that layers of boulder clay extend with but few interruptions as far south as the Wash. We shall mention the other rocks as we progress southwards to the Norfolk coast, but not boulder clay, unless it happens to be of exceptional interest. Meanwhile, please remember that, wherever there is shingle on this long stretch of coast, it must contain many long-travelled pebbles that the waves have washed out of the clay.
Sand-dunes and headlands of hard sandstone are the prominent features of the coast between the mouth of the Coquet and Tyne-mouth, but industrialization has almost ruined its former beauty. It also mars most of the Durham coast. The section between the Tyne estuary and Hartlepool possesses features of unique interest. These are the cliffs of magnesian limestone, a variety of limestone containing magnesium carbonate and of a yellow colour. The Dolomites, the mountain range in the Southern Tyrol, are made of this stone. Hence it is sometimes called dolomitic limestone. It is hard and crystalline, but the battering effect of the waves upon cliffs of this kind of limestone produces curious effects. It cuts capes and arches in it, and fringes the coast with stacks or islets. These features are seen to the best advantage in Marsden Bay. Where there is shingle on the magnesian limestone coast it contains, of course, numerous pebbles of that stone. Their texture, especially that of freshly broken pebbles, is attractive. It displays a fine-grained, yet crystalline, mosaic. The other components of the shingle are pebbles of sandstone, grit, shale and whinstone brought by southward drifting from the Northumbrian shore and ice-borne pebbles from Cumberland, Northumberland, Scotland and Scandinavia.
Industry has brought to the Durham coast, not only the un-sightliness which seems to be its inevitable accompaniment, but also two alien and unpleasing deposits. There are dumps of ballast between Crimden and Hartlepool; at Easington waste material from the collieries has been pitched over the cliffs, despoiling the beach below and blackening the beaches to the south, whither the longshore drifting remorselessly carries the rubbish.
We come now to the long coastline of Yorkshire, which has some impressive cliff scenery and many beaches attractive to the pebble-collector. Cliffs of rock do not appear until we pass south of Saltburn, then shale cliffs rise to commanding heights. In the lovely sweep of Runswick Bay is an interesting beach, but the coast beyond Kettleness is not exciting until we approach Whitby. We have already referred to Whitby at some length, firstly in connection with the ammonites in its shale rocks, and then with the jet for which it is famous. A hard shale promontory called Saltwick Nab lies to the east of Whitby, and from this point a fine line of cliffs, shale and sandstone, extends to Robin Hood’s Bay, a glorious sweep between magnificent headlands. About three miles to the south there are good pebbles in the little bay of Hayburn Wyke.
We are now approaching Scarborough along cliffs of oolitic limestone and sandstone, but the rocks are hidden for much of the way by boulder clay. The hard sandstone headland jutting out from Scarborough offers a stiff resistance to the erosive powers of the waves, but it contributes many pebbles to Scarborough’s lovely beaches. So do the other rocks of the district: shale, limestone and grit. Scarborough is one of the haunts of the inveterate pebble-collector. He finds here an assortment that should satisfy the most persistent, for, in addition to the pebbles formed from the local rocks and the abundant glacial drift, there are many that have travelled southwards from Scotland, Northumberland and Durham. All the sedimentary rocks that we have noted on our passage from Berwick-on-Tweed produce many fossil-bearing pebbles and there are not a few agates, carnelians, and other members of the translucent silica family.
The next beach of interest is Filey Bay, protected on the north by Filey Brigg, a fine promontory composed of grit. The rock of the cliffs that fine the bay is oolitic limestone, but most of it is hidden by huge masses of boulder clay. The barrier of Filey Brigg holds up the southward drifting of pebbles from the north, but they make their way round in time, so the shingle of Filey Bay is varied and well repays a visit.
We are now on the verge of a huge expanse of chalk country. About four miles south of Filey fine, white chalk appears. It forms a range of chalk cliffs all the way to Flamborough Head and thence on to Sewerby. Chalk is almost always accompanied by layers and nodules of flint. One of the rare exceptions is the line of cliffs south of Flamborough Head. They are free from flint. Those on the north, however, are flint-bearing. Look out at Sewerby for a raised beach, formed before the Ice Age altered the shore level. It lies between the boulder clay and the chalk.
From Sewerby, where the chalk disappears, just south of Flamborough Head, to the Wash, there are some eighty miles of coast. Behind it, the chalk runs back into Yorkshire and Lincolnshire for miles, but on it no chalk is to be seen. The beaches are backed almost entirely by boulder clay. It is a coastline which shows most markedly the effects of the Ice Age and also the erosive effects of the tides upon shores unprotected by hard rocks. Flintless chalk puts up little resistance to the waves, because no shingle beds of flint pebbles accumulate below the cliffs to form a defensive barrier. There is geological evidence that the tides had severely eroded the soft chalk before the glaciers covered the coast with thick layers of boulder clay. This also is subject to erosion, but the multitude of pebbles it contains helps to form a beach, which gives some defence against the tides. Nevertheless, it has been estimated that in the last 1,500 years the sea has gained on the land from Sewerby to Spurn Head to a depth of 1-J miles. The list of lost towns on this coast is of melancholy length. Erosion still goes on. In the latter half of the nineteenth century it went on at the rate of nearly two yards per annum.
The longshore drifting of beach material to the south between Flamborough Head and Spurn Head is unusually rapid. There is comparatively little shingle on the beaches. The waves carry it quickly down the Holderness coast to Spurn Head, where, with sand, it forms a spit about three miles long pointing in a S.S.E. direction. The growth of this long nose has been rapid and the Spurn Head lighthouse at its tip has often had to be moved.
Much of the beach material from the Holderness coast is carried farther south to Lincolnshire and beyond.
Before we look at the Lincolnshire coast we must visit the south bank of the Humber near Barton. Here there is a raised bed of shingle running inland for some distance. The Humber may have deposited the pebbles when its estuary was wider and its bed higher. Leaving the Humber, we make our way down the Lincolnshire coast. It is flat but not depressing, as it has many sandy beaches, fringed by sand-dunes. The shingle, made up of the pebbles from the boulder clay and the material brought southward by beach drifting, is consistently interesting, but after we have progressed three miles south of Skegness and turned southeastward to the Lincolnshire side of the Wash, our interest wanes, because there is no shingle until we reach the Norfolk side. On that side we find extensive beds of it opposite Snettisham. Longshore drifting has carried it into the Wash from the north Norfolk coast. This trend, you will note, is opposite to the general direction of drifting (north to south) along all the east coast of England. Somewhere near Sheringham the Norfolk beach material travels westward along the Norfolk coast and then southward into the Wash, but, east of Sheringham, the pebbles follow the general trend of east coast drifting and travel south-eastward down that coast. The reason for this exception to the general rule becomes clear when you look at a map of England. Norfolk bulges out into the North Sea. Its north coast runs roughly E.-W. The waves of the North Sea approaching from the north-east strike that coast obliquely and carry the shingle towards the Wash, but, beyond Sheringham, the coastline begins to turn southward and the waves then drive the beach material down the coast towards Suffolk. Changes of wind, and therefore of wave direction, produce other results, of course, but the dominant winds always prevail in the end and effect this exception to the general tendency of east coast pebbles to make their way southward.
The shape of Norfolk is also responsible for the slowing down of this movement of beach material. Another glance at the map will show why that is so. Its protrusion so far out into the North Sea makes it a gigantic barrier against the southward drift of pebbles down the coast. This accounts to some extent for the fine stretches of shingle on the north Norfolk beaches. Ultimately, of course, the pebbles west of Sheringham are forced round the corner and travel down to join the extensive shingle beds on. the Suffolk coast.
A very shallow sea creeps in and out of the Wash and on the Norfolk beaches to the east of it, so the distance between high-and low-water marks is very great. Between them there are expanses of sand and mud. The waves that wash the shores of a shallow sea have very little transporting power when the tide is in, because they have broken far away from the shore. Beds of boulder clay, deposited by glaciers on the bed of the sea, are eroded by these distant breakers and their pebbles are carried along in a direction parallel to the beach. They form spits of shingle out beyond the flats of sand and silt. These ‘offshore bars’ are a conspicuous feature of this most interesting coast.
Making our way eastwards from the Wash, we come to Hunstanton, which lies at the edge of a large tract of chalk country extending nearly to Sheringham. The chalk outcrops impressively at Hunstanton in high and almost vertical cliffs. These are the last rock cliffs of any prominence that we shall see until we have made the long journey to the North Foreland in Kent. It must not be inferred from this statement that all that huge stretch of coast is dull, flat and uninteresting. On the contrary, much of it is exciting, especially to the pebble-collector.
The Hunstanton chalk is not uniformly white. The upper cliff consists of white chalk; beneath it is a stratum of red chalk about a yard thick, containing ammonites and other fossils; the base of the cliff is a layer of a variety of sandstone, known to geologists as carstone. It contains minute grains of iron ore of a dark brown colour. The sea abrades the bottom of the cliff, undercutting the white chalk and, from time to time, masses of the upper chalk cliff crash down to the beach. There the waves break up the blocks, releasing the hard flints. Pebbles of flint consequently make up a high proportion of the shingle.
Beyond the cliffs is a long line of sand-dunes bordered by shingle. This beach pattern goes on, with slight variation, to Bran-caster and beyond. A good pebble beach separates Brancaster golf-course from the shore sand. A little farther along we come to the fascinating Scolt Head Island, one of the areas under the protection of the National Trust. Extending from Brancaster Harbour to Burnham Harbour, the island is four miles long. A shingle beach runs all the way along its northern side and from it broader ridges of shingle branch out southward towards the mainland. Marshes he between these ridges. The island is a most striking example of the effects of the transportation of beach material by the tides. Experts who have investigated the movements of shingle on this part of the Norfolk coast have come to the conclusion that the island originated as an offshore bar. The constant drifting of shingle to the west lengthened it in that direction. From time to time, however, winds and waves from the north-west held up the westward prolongation and curved the tip of the shingle southward. Each of the southward-branching ridges was probably produced in this way. The island continues to grow ever westward as the dominant winds bring beach material to lengthen it in that direction. Almost all the pebbles in these beds of shingle are flint, derived from the white chalk that the sea has eroded.
Sand-dunes, marshes, shingle spits and offshore bars continue to be the characteristic of the coast as we go eastward. Spreads and ridges of shingle he to the east of Wells Harbour and, as we approach Morston, we see more beds of shingle and a long bank of it above the level of the present beach. It is a raised beach and was probably formed before the end of the Ice Age. We are now very near to a huge stretch of shingle extending for miles, the longest pebble ridge on the Norfolk coast. This is Blakeney Point. Beginning at Weybourne it runs for 1 miles westward to its tip, Far Point. As on Scolt Head Island, branching ridges of shingle run off here and there in a southerly direction, marking, as on the Island, the stages in the growth of the spit. The direction of drift is also westward. In fact, the similarities between Scolt Head Island and Blakeney Point afford some evidence that each of them originated in the same way, as an offshore bar, the former developing into an island, the latter into a spit.
The Blakeney Point pebbles are of flint from the local chalk, Norwich red crag from Sheringham and assorted material from the boulder clay scoured from the bed of the very shallow sea. Winter winds sometimes lash this sea to fury and it then makes breaches in the ridge. The most noteworthy effect of these storms is that the Blakeney Point pebbles show very little grading. They are mixed together, big and little, for most of the length of the ridge.
Returning now to Weybourne, we find ourselves at the beginning of another fine stretch of shingle that runs below the cliffs of boulder clay all the way to Sheringham. Flint pebbles are abundant, mixed with others of diverse origin eroded from the glacial deposit. As the boulder clay persists as far as Happisburgh, over 20 miles away, the beaches below the clay are fed from the soft cliffs with a never-ending supply of ice-borne pebbles that have travelled far and cannot fail to hold the interest and rouse the curiosity of the collector. The cliffs themselves are of special interest to the geologist, for certain sections of them unfold to him the history of the Ice Age deposits on the North Sea coast. They rise above the attractive beach of Sheringham about 100 feet. The Sheringham and Cromer beaches he on a platform of chalk that the waves have cut down. This chalk is the source of enormous numbers of flint pebbles that abound on the beaches of these pleasant resorts and elsewhere on the north and north-eastern coast of Norfolk. Cromer is another Mecca for the pebble-collector. There are fossil-bearing flints and glacial pebbles galore, milky quartz and occasional agate, chalcedony and carnelian. Pieces of Whitby jet are sometimes found and, more rarely, amber. As we have now passed Sheringham, you must remember that we have got back into the region of the southward drifting of beach material. It goes on without further interruption all the way to Dover.
There is low coast from Happisburgh right down to Yarmouth, but it is certainly not dull. Its pattern resembles that of the coastline to the east of Blakeney Point in its dunes and its shingle ridges lying far out beyond high-water mark. The main difference is that the shingle is not broken up into offshore bars, but is continuous for a very long way. Boulder clay and southward drifting are the chief contributions to this shingle. At Yarmouth we have one of the outstanding examples of the effects of longshore drifting. In Yarmouth’s earliest days its inhabitants had to wage long and costly battles against the accumulating pebbles washed down from the north and blocking up the mouths of the rivers Yare, Waveney and Bure. A long spit of sand and shingle ran down the coast from Caister, through which the fishermen of Yarmouth cut channels from time to time to give free passage to their boats. In the fourteenth century the spit had grown so far to the south that the river Yare could not reach the sea above a point only 2£ miles north of Lowestoft. The Yarmouth people must have had more than enough of shingle, yet those of Lowestoft now wish for more. They need it to protect their exposed coast. Much of the shingle which would have drifted southwards from Yarmouth to Lowestoft is held and piled up behind the Gorleston piers. The coast from Gorleston to Aldeburgh, over 30 miles in all, bordered by soft cliffs of boulder clay, gravel and sand, has suffered severely from erosion. It has some fine shingle beaches. Here again there was a surfeit of shingle. Little harbours that were in existence in the fourteenth century have ceased to exist, having long ago been blocked up with shingle after repeated efforts to cut channels through the ridges. Covehithe Ness is the most impressive of the pebble accumulations on this piece of coast, but the pebbles of all the Norfolk and Suffolk beaches are interesting, as indeed they are on most of the east coast.
Proceeding beyond Aldeburgh, we come to the greatest expanse of shingle on all that coast, Orford Ness.
Pebbles from Orford Ness drift down that coast and form a spit across the mouth of the river Deben. Southward drifting has created a much bigger mass of shingle at the mouth of the Orwell. It is the promontory called Landguard Point, jutting out to the south beyond Felixstowe. The beach of that resort is of never-failing attraction to the pebble-hunter. Among the innumerable pebbles of flint are many of quartz and some of jet that has drifted down from Whitby, chalcedony, agate, carnelian and jasper. You may even be lucky enough to find a piece of amber. Also there are chocolate-coloured pebbles which are peculiar to the Suffolk coast and therefore deserve some explanation of their origin. They were derived from the London clay, which, together with red crag, is the cliff material from Harwich to Frinton. The name ‘London clay’ is given to that expansive layer of clay that not only lies below the metropolis but extends beyond it for many miles. ‘Red Crag’ is a deposit laid down before the Ice Age. It consists of reddish-brown shelly sand derived from old banks of sand and shells.
The London clay lies below the crag and runs out beneath the shallow sea. During the ages that have elapsed since this coast was formed the sea-water has effected some chemical change in the clay. The chocolate stones, scoured by the sea out of its bed, are the products of this change. It was found that these stones possessed the properties of a natural cement. Known locally as cement-stones, they were dredged up from the sea-bottom, taken to mills in Harwich and ground into cement.
Another curious feature of this stretch of the Suffolk coast is a layer, below the red crag, of fossil bones and teeth of sharks and other creatures, mixed up with lumps or pebbles from the London clay. Bones contain a high percentage of phosphate of lime, which, as everyone knows, is excellent manure. A great Cambridge mineralogist of the early nineteenth century discovered that all these lumps had become so imbued with phosphate that they were likely to be of the greatest use to farmers. Hundreds of tons of the phosphatic nodules were carted away from the Suffolk beaches to mills in London, there to be ground to powder and sold to farmers as manure. They have a smooth surface, the soft clay having been hardened by the phosphate of lime, and they are reddish-brown in colour. The local name for them for many years was ‘coprolites’, because it was erroneously thought that they were the fossilized droppings of the creatures whose bones were deposited in the Suffolk bone-bed (Greek: Kopros = dung).
There are some good and varied beds of shingle at the Naze and between Frinton and Clacton. The St. Osyth marshes are bordered by a broad stretch of pebbles, but this is the last section of the east coast to appeal to the collector until we get beyond the mouth of the Thames. Mud-flats, saltings and marsh creeks are the main feature of the south Essex coast.
The Kentish side of the estuary, bounded by London clay, is also marshy until we pass the Isle of Sheppey, and it remains flat and dull to Seasalter. Then the London clay rises out of the mud. Cliffs of it run almost all the way to Reculver, where, at last, we come upon a sandy beach extending nearly to Birchington. We have now reached the Isle of Thanet, a chalk ‘island’, which was separated from the rest of north-east Kent by a strait almost 2 miles wide until the sixteenth century, when the strait dried up, leaving a broad belt of alluvium from the Reculver area on the north coast to Pegwell Bay on the east. The rivers Wantsum and Stour now lie roughly in the former channel. The chalk of the Isle of Thanet comes out on the north coast in a line of fine sheer cliffs, of which the eastern extremity is the North Foreland, where the cliffs turn southward to Ramsgate. There they end and give place to the broad sands of Pegwell Bay and Sandwich Bay, which lie at the eastern entrance of the former strait. Behind them the river Stour runs through the belt of alluvium.
It is here, in Sandwich Bay, that we find two extensive and interesting beds of shingle. One of them runs from Ebbsfleet to Stonar. If we ignore a break in it at Richborough, it is about 3 miles long. The river Stour encloses it in a loop which narrows down to a very small opening at Richborough. Nearly all the pebbles are of flint. They have drifted down from the chalk of the Isle of Thanet. The other bed is nearer the sea. Beginning at Deal, it runs up the coast for 1 miles in the form of a spit. Its pebbles are also of flint, but they are derived, not from the Isle of Thanet chalk by southward drifting, but from the chalk south of Deal by northward drifting. Consequently, the pebbles of these two beds have been accumulated by drift in two precisely opposite directions, an anomaly which has yet to be explained.
The pebble beaches of Sandwich and Deal are well worth exploration. Among the many flints there are pebbles of quartz and its chalcedonic varieties. Some excellent specimens of carnelian and sard have been found there. Coming round the corner of the South Foreland from Walmer, we see the high, white cliffs of Dover rising vertically from the beaches. The chalk continues nearly to Folkstone, contributing thousands of flint nodules to the shore. They help to some extent to slow down the erosion. (B) THE SOUTH COAST : DOVER TO LAND’S END Now that we have turned the corner into the English Channel, we must keep in mind all the way to Land’s End that the trend of longshore drifting is up the Channel, that is from west to east, and that on nearly every shingle beach we shall find pebbles that have travelled there from more westerly beaches. Much of the shingle at Hythe and Dymchurch has drifted up from the vast spread at Dungeness.
So we come to Fairlight from the flat coast of Romney Marsh, to find a fine of cliffs running westward through Hastings to Bex-hill. They are composed of clay and sandstone. The latter is finegrained and of a pale yellow colour. Many pebbles formed from this rock are to be found on the Bexhill, Hastings and Fairlight beaches, mingling with abundant flints and brown, red and grey quartzite, shale, chert and grit. At the Pevensey Levels, beyond Bexhill, we come upon the eastern end of the great shingle bed that runs here all the way from Eastbourne. Known generally as the Crumbles, sometimes as Langley Point, it is a pebble beach vast enough to satisfy the most voracious of pebble-seekers. Some of the fulls are over a mile long. The chalk of the Beachy Head cliffs has contributed flint pebbles galore to the Crumbles. A belt of greensand country comes down to the sea between Eastbourne and Pevensey and from it have come numerous pebbles of chert. Eastward drifting has brought to this beach some far travellers from the south-western coast to relieve the monotony of the endless flint and chert. Pebbles of granite, grit, quartz, quartzite of several colours and a few pieces of agate, carnelian and other translucent stones reveal themselves to the discerning searcher.
Eastbourne beach also has plentiful and interesting shingle, which is impeded to some extent from drifting eastward by groynes. Beachy Head also helps to slow down the movement of beach material as it acts as a huge, natural groyne. This magnificent headland is the point at which the South Downs meet the sea. Its vertical cliffs, 500 feet high, of white chalk are a most impressive introduction to the chalk coast of Sussex. The cliffs go on with very little interruption through Seaford, Newhaven, Brighton, Shoreham, Worthing and Littlehampton, almost to Bognor Regis, where the chalk country ends. There are shingle beaches of good quality for most of the way. Naturally, the most prevalent pebbles are of flint, but longshore drifting has added to them many and varied pebbles from more westerly beaches. The most striking sections of coastline are between Beachy Head and Cuck-mere Haven, where the clean, white chalk of the Seven Sisters rises almost vertically, and between Rottingdean and Brighton, where a sea-wall protects the fine, chalk cliffs from erosion. The spit of shingle at the mouth of the river Cuckmere deserves to be visited. Here and at many other parts of the Sussex chalk coast we can see the effects of erosion upon the cliffs, for the sea washes over a chalk platform from which the now vanished cliffs for- merly rose. Those cliffs stood much farther out to sea. The material of which they were made has produced inexhaustible supplies of shingle. Yet even that quantity is insignificant in comparison with the huge mass of land that formerly connected Britain with France. That great isthmus consisted almost wholly of chalk. It disappeared in comparatively recent geological times, possibly at the end of the Ice Age, some 10,000 years ago. The chalk that now lies beneath the Straits of Dover has yielded an incalculable amount of flint pebbles to the beaches of our southeast coast.
To all its visitors except the most zealous of pebble-collectors Brighton beach seems to have far too much shingle and also too much of the same kind. Yet, over a century ago, it was one of the haunts of those who took up the then fashionable pursuit of collecting pebbles for the display cabinet. They collected and laboriously hammered flint pebbles in the hope of finding an internal surface that revealed fossilized remains in a pleasingly intricate pattern. These they would take to the local lapidaries for cutting and polishing. Of the thousands who now throng the Brighton beach, how many are thus engaged? Perhaps none, but there are still many fossiliferous flints there and many a flint pebble would repay the cost of its fashioning in the pleasure it gives to the beholder.
Shingle abounds between Shoreham and Worthing. The eastward drifting of it has turned the mouth of the river Adur more than a mile to the east. It was a constant menace to Shoreham Harbour until the building of the protected opening to the harbour in the last century prevented further blockages. Much of the great shingle beds at Lancing and Shoreham now lies above the high-water mark of ordinary tides, but storms hurl it inland and thus broaden the pebble bed. There is somewhat less shingle as we go west of Worthing towards Littlehampton. We are now passing out of the region of chalk cliffs and making our way along a comparatively low coast to Bognor Regis, where the chalk gives way to London clay, sandstone and sandy limestone. Pebbles from the neighbouring Selsey Bill and from the Isle of Wight drift eastward along this stretch of coast.
Selsey Bill has much the same shape as Dungeness. It is in every respect a ‘ness’, but it lacks the huge expanse of shingle that has accumulated to form the latter. Formerly an island, it is still virtually so, because a low-lying marsh running from Bracklesham Bay to Pagham Harbour almost separates it from the mainland. The Bill and the foreshores on each side of it consist of a soft sandstone known to geologists as the Bracklesham Beds. Selsey and Bracklesham Bay are famous for the large range of marine fossils that are found in these beds. On both coasts of the Bill there is good and varied shingle, much of which is derived from drifting from the beaches of Hampshire, the Isle of Wight and farther west. The shingle on the western side of the Bill is unstable. If gales blowing up the Channel coincide with high tides they wash away many of the pebbles.
We now reach a complicated section of coast, heavily indented and geologically varied. This is the stretch from Chichester Harbour to the western entrance to the Solent, with the Isle of Wight lying to the south. The simplest plan will be to take first the mainland coast, as it demands much less attention than the more attractive beaches of the Isle of Wight. In each case it is essential to remember that the direction of longshore drifting is eastward.
Alluvium and mud-flats characterize much of the mainland coast. Apart from the chalk of the Appledram, Emsworth and Havant coast, and of the northern parts of Thorney, Hayling and Portsea Islands, clay, sand and gravel soils constitute the mainland. Shingle beaches, consisting mainly of pebbles of hard chalk and flint, line this coast but not continuously. There is a long strip of shingle at Portsmouth Harbour and a very broad and deep one on the south-western corner of Hayling Island.
The relative hardness of the Isle of Wight rocks has determined the lozenge shape of that island. A high ridge of chalk runs across the island from the Needles in the west to the gloriously white Culver Cliff in the east. Limestone, marl, sandstone and clay make up the ground to the north of the chalk ridge. To the south there are sandstone, limestone, shale, marl and clay, but in the southeast the chalk rises again to form the highest part of the island. There is such similarity between the rocks in the north of the island and those on the Hampshire side of the Solent on the one hand, and between the rocks of the rest of the island and those of the Swanage district on the other, that the former union of the island with the mainland can be easily understood. Land once lay between the Isle of Wight and Hampshire, Bournemouth Bay and the Isle of Purbeck.
The chalk out of which the Needles have been cut is very hard, much harder than the white cliffs we have already observed at so many places on this tour of the coast. Since they were deposited they have lain undisturbed but the chalk of the Needles and the adjacent ridge was folded over by earth movements under great pressure. It was this pressure that hardened the Isle of Wight chalk. It accounts for the projection of the ridge into the sea at the western extremity of the island. The waves have more easily eroded the softer rocks lying to the north and south of the Needles. Thus the island has acquired its shape.
The pebble beaches of the Isle of Wight are a rich deposit of stones that gladden the collector. In addition to the predominating flint, limestone and sandstone derived from the island’s rocks, there is a most gratifying variety of other pebbles. From Culver Cliff through Sandown and Shanklin to Luccombe there is excellent shingle. The beaches of Bonchurch, Ventnor and Niton are equally satisfying. The quartz family is well represented from pure quartz or rock crystal to jasper. Agate and carnelian can also be found. Sandown Bay is peculiarly rich in fossil-bearing flint pebbles. Many of them contain fossil sponges with beautifully delicate spicula.
Before we proceed further to the west we must glance at a shingle spit of no little interest on the mainland. This is the Hurst Castle spit between Christchurch Bay and the Solent. It runs out to sea in a south-easterly direction for over a mile, then turns to the east for about half a mile, throwing out lateral ridges to the N.N.W. The first of these three sections demonstrates the eastward drifting of beach material, the second shows that the spit had reached deep water and must take a left-hand turn to continue its growth, and the lateral ridges show the effect of northeast. winds blowing down the Solent and causing the spit to bend backwards.
The spit is a continuation of the long bed of shingle on Milford beach. From this beach cliffs of sand and clay line the long sweep of Christchurch Bay for some miles and their erosion brings down material to the foreshore. From observations of the movement of this material it has been concluded that strong south-east winds drive more of it westward than is driven eastward by south-west winds. Consequently, this part of Christchurch Bay furnishes an exception to the general tendency of drift along the south coast. On the other hand, a long spit of sand and shingle runs back from Hengistbury Head at the western end of the bay for over 2 miles though only the first £ mile is stable. Much of this shingle, including very large pebbles of flint, has travelled eastward round Hengistbury Head from Bournemouth Bay.
The coast of that bay is of clay and sandstone and its shingle is similar to that of Christchurch Bay. Poole Harbour and Studland Bay have attractive dunes, saltings and sandbanks, but little shingle of interest. We have now reached the Isle of Purbeck, which has a coast of great beauty and variety. In its alternating hard and soft rocks it clearly shows how the former resist erosion and how the latter yield to it. The technical term for this is ‘differential erosion’, and we shall have occasion to notice it when we survey the west coast.
The first of the hard promontories that we see is Ballard Point, with the Old Harry rocks and the Foreland. The vertical cliffs of hard, white chalk are part of the same chalk ridge that traverses the Isle of Wight. To the south of the chalk is a broad belt of clay, which the sea has cut back to form the lovely Swanage Bay. Then come hard rocks again. They are of Purbeck limestone, a hard, compact stone widely used in the decoration of important buildings. The pebbles formed from it respond well to polishing. Turning to the west round Durlston Point, we see a long line of high vertical cliffs, with Portland stone in the lower, and Purbeck stone in the upper, part. Portland stone is another hard limestone in much use for building. It contains many fossils. In these cliffs are nodules of chert.
As soon as we pass St. Alban’s Head, we find the coast cut back, because the hard rocks have been underlain by clay, with some layers of shale and limestone running through it. This clay, of a very dark grey colour, is known as Kimmeridge clay, taking its name from Kimmeridge Bay on this piece of coast. It appears in many other parts of England.
In the next 5 miles is to be found some of the most delightful coast scenery in England, from Worbarrow Bay, past Mupe Bay, Lulworth Cove, Stair Hole and Durdle Door to Bat’s Head. The hard rocks are Portland and Purbeck limestone and chalk. At Worbarrow Bay and Lulworth Cove the sea has broken through the outer defences of Portland stone and, having eaten away the layer of clay behind, is now trying to erode the chalk, which forms the inner defences. In these and other bays on the south side of the Isle of Purbeck, the pebbles are graded in an unusual manner, the larger being in the centre of the bay, the smaller at the sides. Most of the pebbles are of hard chalk, flint, chert, Purbeck limestone, Portland limestone, and sandstone, with an admixture of varieties from the beaches of Weymouth, Devon and Cornwall.
From the Isle of Purbeck to the Isle of Portland we have the coast of Weymouth Bay. It is a geological inter-mixture of chalk, gault, greensand, clay, grit and Purbeck and Portland limestones, so the shingle of the beaches is well varied. Two large belts of shingle must be specially mentioned. One of them runs down the west side of Weymouth Bay for about 2 miles. The pebbles decrease in size as the shingle approaches Weymouth beach, which consists mostly of sand. Flint pebbles predominate in this belt. The other is Portland beach. It runs up from Portland towards
Weymouth for 1£ miles and has been formed of pebbles derived from the two limestones, Purbeck and Portland, of the Isle. The building of Portland breakwater has retarded the growth of this beach. Although it is in contact with Chesil Beach at one part, it is geologically quite distinct from it.
From Bridport (which, you may recall, is the western end of Chesil Beach) to Sidmouth and beyond the rocks of Lyme Bay are of many kinds. In their variety they produce coast scenery of no little charm. Blue and yellow cliffs of shale and limestone face the beaches for some miles around Charmouth and Lyme Regis; those of Seaton and Sidmouth consist of red marl, and those of Budleigh Salterton are of dark red sandstone, but here and there we find chalk, chert, shale, greensand and clay. On the cliffs between the mouth of the Axe and Lyme Regis the strata of chalk, clay and greensand lie upon the limestones, shales and marls at an angle which sometimes slopes towards the sea. If the sea undercuts the cliffs at those points the upper strata may slide over the lower and plunge downwards. There have been some spectacular landslides of this kind. One at Axmouth in 1839 produced the collapse of eight million tons of earth. Great mounds of it lay on the beach and a huge ridge of greensand suddenly rose out of the sea. Erosion has since disposed of the ridge and the mounds, adding copious material to the shingle of the Lyme Bay beaches.
The pebbles of these beaches are mostly flint and chert, but there is much limestone, sandstone and shale. The biggest spreads of shingle are the spit which turns the mouth of the Char to the east and the long belt that runs with little interruption from Branscombe for some miles towards Sidmouth.
On the other side of the river Otter are the cliffs of Budleigh Salterton. They are of dark red sandstone. In these cliffs there lie exposed the extraordinary pebble-beds which all pebble-collectors should strive to visit, for from this deposit pebbles of unusual interest have travelled eastward to most of the beaches on the whole of the south coast of England. They are all well rounded, having been transported to Budleigh Salterton, it is believed, many millions of years ago by turbulent water that poured from the west over land now beneath the sea. Most of the pebbles are of dark brown quartzite and grit.
Soon after passing Budleigh Salterton we enter upon a red coast, the rocks of which are formed of sandstone, clay, marl and breccia. These formations continue all the way to Babbacombe, near Torquay. The word ‘breccia’ is of Italian origin and means the rubbish of broken walls. Breccia is formed when a mass of rock is fractured by the great pressure of earth-movements and the rock is crushed into small angular fragments. These fragments become consolidated by a process of natural cementation. Consequently, a breccia resembles a conglomerate, but in the former the fragments are angular and in the latter they are rounded. Pebbles of breccia are very attractive, especially when cut and polished. The shingle of this coast yields some good specimens of them, among many of red sandstone. Langstone Point on the western side of the Exe estuary is formed of breccia and bands of it appear in the cliffs for most of the way to Dawlish.
There is good shingle in the Teignmouth district. The bar of shingle and sand at the mouth of the river Teign, running to the north-east from the Ness, fluctuates in size and in shape according to the severity of tides and winds.
As we proceed southward along the Devon coast we come to a region of much older and more diverse rocks. Hitherto we have encountered few rocks that were not of sedimentary origin, but now in Devon and Cornwall we shall come upon many that are igneous and some that are metamorphic. The formations are of great complexity and the scenery is therefore most pleasantly varied. Limestone, slate, sandstone, shale, grit and dolerite make up the rocks of Torquay and Torbay. The pebbles formed from these rocks predominate in the shingle of the beaches. There are good ridges of shingle on Oddicombe and Babbacombe beaches. Of the two Torquay promontories, Black Head is a tough mass of dolerite, and Hope’s Nose is of limestone. Going south through Paignton we pass along a coast of red sandstone, but near Broad Sands and its pebble ridge we enter a limestone area. The Brixham cliffs are of limestone and so is Berry Head, the promontory at the southern end of Tor Bay.
On the other side of Berry Head we come to Start Bay, a wide sweep, on which the pebble-hunter will find much to occupy himself, for, between the estuary of the Dart and Start Point, a distance of some 10 miles, there is a series of shingle beaches of exceptional interest. The pebbles are well rounded and are derived from the diverse rocks that line this lovely coast: sandstone, grit, shale, green schist, quartzite, slate, red slate and dolerite. There are also pebbles of granite, brought down to the beach by the river Dart from the granite mass of Dartmoor.
In the middle of Start Bay is a bed of shingle that must not be missed. This is the extensive bar at Torcross that encloses the lagoon called Slapton Ley. There is one very unusual feature about it. Its pebbles do not come from the rocks of the Bay. Many of them are flints, yet there is no chalk or other flint-bearing rock near to Torcross. The other pebbles are quartz, including very small ones that are pear-shaped, and granite from Dartmoor. A smaller but very pleasant shingle beach that is somewhat similar is at Blackpool , between Slapton and the Dart estuary. Another good belt of shingle lies above Bee Sands, between Slapton and Start Point.
Start Point, Prawle Point, Bolt Head and Bolt Tail form the southern tip of Devonshire. These rugged promontories are made of metamorphic rocks of extreme age, green schist and mica schist veined with quartz. A freshly broken piece of mica schist has a beautiful lustre.
From Bolt Tail to Plymouth the coast continues to be impressive. It has headlands of hard sandstone with occasional dolerite. There are no great expanses of shingle, but its pebbles, many ofwhich have drifted from the Cornish beaches, are of unfailing interest. Plymouth’s pretty cliffs are composed of limestone, containing many unusual fossil corals, of types only found here and at Torquay.
The enchanting coast of the Cornish peninsula now lies ahead of us. From Plymouth Sound to Mevagissey most of the chffs are formed of slate and grit. They are mainly grey in colour, but there are variations from green to red. The slate varies also in its texture and durability. Some of it is hard and glossy, but some of it approximates to shale of a muddy kind. Pebbles of this rock are not very attractive, but many of them have veins of quartz and these look well when polished. There are few shingle beaches of any extent east of Mevagissey. Igneous rocks, mostly of dolerite, are to be seen in the headland beyond Par. The shingle becomes more frequent, but in small beaches, between Veryan Bay and the Lizard; all of it is good and is a representative assortment of the diversified rock structures.
The Lizard peninsula is unique in the rich colouring of its cliffs and in the nature and formation of its rocks. These are so complex that only a geological map of large scale can show them clearly and in detail. Briefly, the predominant rock is serpentine, both green and mottled red. It gives the Lizard cliffs their glorious colours from Cadgwith nearly to the Lizard Point, which is a mass of schist, and right round for most of the way from Kynance Cove to Mullion. Innumerable dykes of gabbro run through the serpentine and come out on the face of the cliffs. Gneiss, in beautiful foliations, is seen to best advantage in the Man o’ War Rocks, bands of quartzite and dykes of granite run through much of the schist, and pebbles of granite travel down the coast from St. Michael’s Mount and Trewavas Head. The pebbles formed from both the green and the yellow serpentine, the gneiss and the schist are particularly pleasing. One of the local industries is the cutting, fashioning and polishing of serpentine, but the serious pebble-collector must not be so absorbed in that fascinating rock as to forget the others that the Lizard provides.
As we continue up the coast towards Mount’s Bay we cross several attractive and rewarding beaches. Then, between Baulk Head and Porthleven Harbour is a straight sandy beach for 2 ½ miles. An extraordinary spread of shingle lies just beyond the middle of this stretch. It is Loe Bar. It encloses the lovely freshwater lake called Loe Pool. The spread is over 400 yards long and 200 yards wide. This is small in comparison with most of the expansions of shingle that we have examined, but it has a peculiar quality. Most of the pebbles are of flint, despite the fact that no flint-bearing strata are to be found in western Cornwall, though there is some in the Scilly Isles. The same peculiarity is to be seen at Prah Sands, about 4 miles farther along. It has puzzled geologists for a long time. It may be that the flints came from rocks which have long ago disappeared as the result of denudation.
The coast from Porthleven to Newlyn is of slate, granite and greenstone. The pebble-collector should linger on the Marazion and Penzance beaches as long as possible, for here he should find many choice specimens for his cabinet. Pebbles of granite, some of them porphyritic, quartz, quartzite, quartz-veined slate, greenstone, serpentine, jasper in various shades, agate, chalcedony, citrine, carnelian and amethystine quartz, together with fossili-ferous flints await his discerning scrutiny. The pebbles of these and neighbouring beaches on the Cornish coast are remarkable, not only for their lustrous beauty when cut and polished, but also for the extent of their geological range.
From Mousehole, round Land’s End to Cape Cornwall, the cliffs are all of granite. They are the edge of the huge mass of granite that forms the western knob of the Cornish peninsula and they present a sturdy front against the fierce Atlantic gales. Their castellated form almost suggests that they have been established there for that very purpose. (C) THE WEST COAST I LAND’S END TO THE SOL WAY FIRTH The long coast we are now about to explore is both deeply and widely indented, as much of it is washed by waves of long ‘fetch’. The dominant wind is from the south-west, so the direction of longshore drifting is northward. When the coast runs from west to east, e.g. North Wales, the trend will naturally be eastward.
The massive granite cliffs from Land’s End to Cape Cornwall contribute pebbles of that rock to the beach of Whitesand Bay. The beach at Cape Cornwall is very limited but it contains a very satisfactory assortment of pebbles. Although granite is the main rock in the cliffs all the way to St. Ives Bay, the greyness is relieved here and there by greenstone, especially between Cape Cornwall and Pendeen Watch. At Porthmeor Cove, one of the many delightful coves on that coast, the rocks are of granite, greenstone and slate. The two biggest promontories, Gurnard’s Head and St. Ives Head, consist of greenstone.
At St. Ives we leave the granite region for a low coast of sandstone, grit and slate. From Carbis Bay to Godrevy Point there are 5 miles of sandy beach, most of which is backed by dunes. There is comparatively little shingle, but it is well worth inspection. The dune coast is succeeded by imposing and rugged cliffs of sandstone and slate continuing for at least 10 miles between Navax Point and St. Agnes Head. At first there is little, if any, beach at the cliff foot, but some shingle lies below the long line of cliffs that edge Reskajeage Downs and at Portreath and Porth Towan. The pebbles, hke those of all the Cornish beaches, are not merely those that have been formed from the local rocks. Sandy shale and slate continue for some miles, though interrupted by the granite of Cligga Head. The Newquay cliffs are of hard, black shale. Perran Beach is a huge expanse of sand, backed by very high dunes. This and the fine beaches of Crantock, Fistral Bay, Newquay Bay, the great sweep of Watergate Bay, Beacon Cove and Mawgan Porth, are of fine, shelly sand with little but very varied and interesting shingle.
Some little distance north of Mawgan Porth, and near Bed-ruthan Steps, we come upon cliffs of sandstone and shale, which go on to Port Isaac, but here and there are outcrops of tough, volcanic rock. This rock forms the headlands, of which the most prominent are Park Head, Trevose Head and Pentire Point. The lava of which Pentire Point is formed is famous for its curious appearance. It resembles a heap of pillows. The rock, known as ‘pillow lava’, was probably erupted in a molten state from the sea-bed.
On this part of the Cornish coast there are raised beaches, usually elevated about 10 feet. One of the best of these is at Tre-betherick Point, near Padstow. The river Camel comes out into Padstow Bay in a wide estuary. It brings down to the coast vast quantities of fine sand. The bar in the bay consists of sand. Geologically interesting as this coast is, its shingle is scanty. We must make our way some distance to the north before the beds become at all extensive. A coast of slate and shale cliffs, with headlands of greenstone, goes on for most of the way to Tintagel. The lovely Trebarwith Strand and Hole Beach are backed by lava, then comes slate again, to be followed by formations of great complexity at Tintagel, where violent earth-movements have caused much thrusting and crumpling.
The igneous rocks disappear at Boscastle, and then come cliffs of shale, sandstone and chert. In fact, the whole stretch of coast from Boscastle to Appledore in Barnstaple Bay may be said to consist of dark shale, sandstone and occasional limestone and chert. There is not much shingle on the sandy beaches of Wide-mouth Bay and Bude. Fragments from the cliffs are more quickly ground by the crushing power of the long Atlantic rollers on this exposed coast than on the more sheltered beaches east of Hartland Point. At that corner, where the coast running north from Bude turns sharply east towards Clovelly, is some of the most impressive cliff scenery in England. The Hartland rocks are of shale and sandstone. A beach of boulders and very large pebbles, mainly derived from these rocks, lies below the cliffs for most of the way from Hartland Point to Clovelly, but only the agile and strenuous pebble-collectors can make their way down to it. Another beach of boulders and large pebbles lies below the cliffs between Pepper-combe and Westward Ho! but the first shingle bed of any great size comes into view at Westward Ho! The rivers Taw and Tor- ridge meet in one estuary to the north of the ridge. The shingle ridge, over a mile long, is a massive accumulation of very large ovoid pebbles and boulders. Most of them are too big to have been carried down by the two rivers. Only longshore drifting from the south-west can account for the accumulation.
There are no cliffs here, but an enormous range of sand-dunes extends from Westward Ho! to Croyde Bay. Baggy Point with its high sandstone cliffs juts out straight, and far to the east, thus hindering the transportation of pebbles from the south. Here again, and at Saunton, where there is some good shingle, the raised beach can be seen. There is regular alternation of slate and sandstone rocks for the next 25 miles. The sandstone of Baggy Point and Morte Bay is succeeded by the slates of Morte Point, Bull Point, Lee, Ilfracombe and Combe Martin Bay. Then comes the sandstone of Trentishoe and Heddon’s Mouth, the slate of Woody Bay, Lee Bay and Lynton, and the sandstone again of Foreland Point and on into Porlock Bay. Shingle, formed mainly from the local rocks, appears in most of the coves. The slates of Morte Point come out in sharp ridges on the lower part of the beach. They are glossy and have veins of quartz running through them. The blue-grey slates and shales of the Ilfracombe coast are also attractive, having a silvery sheen. Shingle, including boulders and large pebbles, lies along the beach of Porlock Bay, and at Porlock the eastward drifting has piled up a small cape of shingle around the harbour. It has also caused a large accumulation at Greenaleigh.
We are now approaching an area of softer rocks: marl, clay, impure limestone and soft shale, beginning near Minehead and going on along the southern shore of Bridgwater Bay to the estuary of the river Parret. These shores are much less exposed to the attack of the Atlantic breakers than those of Cornwall and North Devon and some of them enjoy the additional protection of storm beaches of piled-up shingle. The fine sand and alluvium between Minehead and Blue Anchor lies behind a belt of shingle. The eastward drifting of beach material has formed a large bar of shingle at the mouth of the Parret and has bent back the outlet of the river. It has also added ridges of shingle to Stert Point. There is very little shingle in Weston Bay and only a thin belt of it in Sand Bay. Harder and older rocks have now come into view. The Brean headland is of hard limestone. Massive limestone and old red sandstone are to be seen in the coast rocks between Clevedon and Portishead. The old red sandstone contains many agates. They may be found occasionally among the pebbles.
But we have now reached the Severn estuary, with its low, flat shores, muddy water, deposits of alluvium, and salt marshes. We must cross the estuary to the more open sea beaches of South Wales. As they run roughly east-west the longshore drift will be eastward, until we reach that point in Pembrokeshire where the coastline begins to turn northward again.
Avoiding the alluvium of the Usk estuary and the dock area of Cardiff, we can begin at Penarth Head. This Glamorganshire coast is formed of comparatively soft rocks, of no great height but of no little charm. The vertical cliffs appear to be painted in bands of colour. There are red and green marls, yellow and blue limestones and black shales. A wave-cut platform lies below them, cut from the same rocks. Limestone predominates as we go farther west towards Porthcawl. There are almost continuous cliffs of it all the way to Barry. Below the cliffs are pebble or boulder beaches, formed mostly from the cliff material. There is a large spread of shingle at Aberthaw containing many pebbles from the west. Rocks, mainly of limestone, go on a little way past Porthcawl, giving place to marl and then millstone grit before the shale of Swansea Bay begins at Port Talbot.
At the western end of Swansea Bay we come to the Gower Peninsula, which, in its geological structure and coastal beauty, is of almost unique interest, situated though it is in juxtaposition to a highly industrialized area. The peninsula is a level plateau of limestone, which has been folded by earth-movements. They have also caused thrusts and faults in the strata in many places. There is a considerable amount of old red sandstone, especially at
Rhossili Bay, and of shale, notably in Port Eynon, Oxwich Bay, Oystermouth and bordering Llanrhidian Sands. From Mumbles Head, that juts out into Swansea Bay, cliffs of grey limestone form the south coast of the peninsula almost all the way to its western extremity, Worms Head. Very pleasant bays indent these cliffs at intervals, usually where faults in the strata have aided the attacks of the waves. A wave-cut platform lies below the limestone cliffs. Where there is shingle, most of the pebbles have originated from the limestone, sandstone and shale of the peninsula, the shape of which greatly impedes the drifting of beach material from the west. A glance at the map will make this clear at once. The peninsula runs out due west from the mainland, which is separated from it on its north side by the wide and long Burry Inlet going due east for 8 miles.
A large pebble ridge has developed at the seaward end of Burry Inlet into Whiteford Spit. Most of the pebbles are of limestone and have been transported up the western coast of the peninsula by wave-action, though a great authority has suggested that the source of these pebbles may have been a moraine that has long ago disappeared. A moraine consists of the debris left by a glacier after it has melted. This must remind us that we have now travelled far enough to the north to be back in that part of the country which bears evidence of the Ice Age. Ever since we left the Essex shores we have moved along the coasts of the un-glaciated part of England. Henceforward we shall have to make frequent reference to boulder clay, glacial drift and so forth.
One other interesting feature of Gower is its raised beaches. They can be seen on many parts of the coast on a kind of platform lying between the top edge of the cliffs and the present-day beach.
Returning to the mainland on the other side of Burry Inlet we find a coast of sand-dunes and marsh reaching to the famous sands of Pendine in Carmarthen Bay. After passing the joint estuary of the rivers Towy and Taf, however, we see a series of beaches of very large pebbles and boulders, mostly of limestone and sandstone that have drifted eastward from Pembrokeshire.
We are now about to explore the shores of that county which, to the pebble-seeker, are among the most fascinating in the British Isles. The western coast of Carmarthen Bay, north of Tenby, is mainly of shale, with some sandstone. At Saundersfoot is a shingle beach which has diminished in depth and extent in the last sixty years as the result of the eastward drifting of beach material. In the nineteenth century ships called at Saundersfoot for cargoes of coal. They dumped their ballast on the beach before they took the coal aboard. In course of time a large beach of ballast accumulated, consisting of stones from various parts of the British Isles and elsewhere. When Saundersfoot ceased to export coal, the piles of ballast not only ceased to grow but dwindled, as their material drifted away to the east. The pebble-collector must always have in mind the possibility that a stone on any part of our coast may have travelled there from a heap of ballast, for Saundersfoot is not the only place on the British coastline where ballast-dumping has gone on. One can seldom be absolutely certain of the original source of any pebble.
The very pleasant and largely unspoilt resort of Tenby is at the eastern end of a long series of magnificent limestone cliffs. Between Tenby and Giltar Point, to the south of it, is a fine sandy beach backed, first, by a storm beach of pebbles, and then by extensive sand dunes. The bulk of the shingle comes from the local rocks, limestone, sandstone and shale. The remainder are pebbles of various kinds scoured by the sea from boulder clay and stones from the raised beach at Giltar Point. Some ballast pebbles are also present.
The cliffs between Tenby and Angle are very like those of Gower peninsula in formation and colouring. They consist of grey limestone and, near Angle, old red sandstone, a pleasing contrast. The red rocks are especially striking in Manorbier Bay, Freshwater Bay East and Freshwater Bay West. Good and well-varied shingle lies in many of the delightful bays between Tenby and Milford Haven. Both the northern and the southern shores of the Haven are of the old red sandstone. At St. Ann’s Head we are at the beginning of a coast that is scarcely equalled for beauty, diversity of colouring, stacks, arches and islands in all England and Wales. Vertical cliffs of limestone continue to Broad Haven in St. Bride’s Bay. The rocks of that magnificent sweep possess wide variations of age, hardness and colour. Volcanic rocks are interspersed among sandstone, quartzite, limestone and shale and the cliff colours are black, grey, yellow and purple. Musselwick Bay displays the striking contrast of black shales and old red sandstone. As we go northwards along the shores of St. Bride’s Bay we find the harder sandstone forming the headlands and the softer shale cut back into little bays: another example of differential erosion. The pebbles of the bays have originated for the most part from these rocks, but they are mingled with others of many kinds from the boulder clay. Near the northern end of the bay is the superb beach of Newgale, its fine expanse of sand fringed by a storm beach of rounded sandstone pebbles, many of which have travelled eastward along the northern shore.
The north Pembrokeshire coast from Newgale to Fishguard is even more impressive in its rock structure, the boldness of its headlands and the colouring of its cliffs. This great arm of land protruding westward above St. Bride’s Bay is built of rocks that were laid down in the remotest geological ages: the Ordovician, a period of intense volcanic activity that began about 350 million years ago, the Cambrian, a long period of deposition in which hard sedimentary rocks were laid down, beginning about 400 million years ago and, the oldest of all, the pre-Cambrian, which is believed to have started at least 400 million years earlier still. From Newgale to Fishguard Bay there is a most complex rock structure of Ordovician dark and black shales and volcanic rocks, Cambrian slates, flags and sandstones, red, purple and grey grits, and pre-Cambrian tuffs. The capes from St. David’s Head to Strumble Head are of igneous rock, mostly dolerite. The precipitous cliffs come to a climax in the massive Strumble Head. Boulder clay comes down to the sea in the few sections of low-lying coast. It is very noticeable in the lovely Whitesand Bay and at Porth
Melgan. From all these igneous and sedimentary rocks and from the boulder clay come pebbles of the most varied kind travelling northwards up the coast, held up for a long time by Strumble Head, but eventually rounding it and making their way up the gentler and less indented shores of Cardigan Bay. The beaches of Fishguard Bay and Newport Bay contain shingle derived from the diversified rocks of the Pembrokeshire coast.
We have now reached the southern end of Cardigan Bay. Its very long coast has many beautiful beaches, but it lacks the rugged grandeur of Pembrokeshire and it is much more uniform in its geological formation. All the way to Newquay the coast rocks consist of shales and sandstones. It is also a heavily-laden area of boulder clay, the outcome, it is believed, of the melting of the great ice-sheets that crossed the Irish Sea into Wales during the Ice Age. On many parts of the coast between Strumble Head and Cardigan it lies on the cliffs, sometimes coining down to the beaches. We shall find innumerable flints in the Cardigan Bay shingle. Nearly all of them have been washed out of the boulder clay, which was glacier-borne from the chalk of Ulster across the Irish Sea. Possibly chalk rocks now lying beneath that sea were also scoured by the glaciers.
This is a good pebble coast. Deep and narrow valleys (cwms) have cut down through the soft rocks to little bays. There is shingle in most of these. Some of the pebbles have come down by river from the plateau behind the coast. Some have come from the boulder clay and others have travelled up the coast from Pembrokeshire. Shingle bars have formed on the beaches of Cwm Tydi and Afon Soden.
The boulder clay grows thicker as we go northward. It forms the cliffs of New Quay Bay. There the shore has deposits of large pebbles from the heavy glacial deposit, with storm ridges of the larger stones at the back of the beaches. South of the harbour of the pleasant little town of Aberayron there is an ample spread of shingle, most of it boulder-clay pebbles. The glacial deposit goes on to a great depth, and with little interruption, from Aberayron to Llanrhystyd. The shingle is not continuous, but what there is is well worth inspection. Where the boulder clay does not overrun and obscure the cliffs steep rocks of grit emerge.
We are now nearing Aberystwyth, on the estuary of the rivers Rheidol and Ystwyth. A great accumulation of shingle has bent the mouth of the latter northward. There is smaller, but very good, shingle on the beaches to the north of the harbour. Apart from the numerous flints from the boulder clay and grit pebbles from the local rock there is a diversity of shingle from the igneous rocks of Pembrokeshire. Some nineteenth-century collectors reported that they had secured some small specimens of aquamarine at Aberystwyth. Aquamarine is the blue variety of beryl. It is not entirely impossible for pieces of this stone to have been found here, because it exists in the granite of the Mourne Mountains in N.E. Ireland and could have been transported by ice across the Irish Sea, but we think that even a prolonged search would bring little reward to-day.
High cliffs of grit run on to Borth. On the way we come to the very pleasant beach of Clarach Bay which has a substantial ridge of interesting shingle. There is plentiful shingle a little farther north, where Morfa Borth (or Borth Sands) extends for 2 miles until it joins the estuary of the river Dyfi to the south of Aber-dovey. Across the estuary and spreading out at its mouth is a huge storm beach of large pebbles. Its growth is northward.
The coast rocks from Aberdovey northwards are of grit, slate and sandstone, changing to blue, blue-grey and black slates of the Cambrian Age before we reach Llwyngwril. Here is the beginning of a long shingle beach that eventually develops into the Ro Wen shingle spit that extends right up into the Mawddach estuary. It is a storm beach of large pebbles that have accumulated by northward longshore drifting. Sand-dunes cover parts of it and salt-marshes lie behind it. On the north side of the estuary a shingle ridge of boulder clay pebbles intermingled with shells runs out westward.
Barmouth lies just beyond it. The shingle of the beach off the promenade tends, unaccountably, to drift slightly to the south, that is, in the precisely opposite direction to the movement of beach material on all the rest of this coast.
Soon after we have gone beyond Barmouth we come to the beginning of Morfa Dyffryn, a great expanse of sand-dunes, blown sand and marsh extending for 6 miles from Llanaber to Llanbedr. Belts of shingle border it on the seaward side for parts of the way. The first belt begins near Llanaber railway station and runs for over a mile. Near Tyddyn Mawr it has suffered a broad breach, but it continues beyond the breach for more than a mile to the estuary of the little river Scethin. It has deflected the mouth of that river to the north, thus clearly demonstrating the northward drifting of beach material on this coast. The ridge resumes its northward journey on the other side of the Scethin and goes on for at least another mile. There is no more shingle of any appreciable extent until we come near to Mochras Island, locally known as Shell Island on account of the amazing number and variety of shells on its shores. The island is the remnant of a glacial moraine and is therefore a mass of boulder clay, a storehouse of pebbles and boulders, which form a long spit running to the north-east to the estuary of the river Artro and resuming its way on the other side of the river right up to the boulder clay cliffs of Harlech.
Here we enter another region of sand-dunes, blown sand, salt-marshes and swamp, the great expanse of Morfa Harlech. In many ways it is like Morfa Dyffryn. Each is triangular in shape, with the apex of the triangle at the south, and each is a flat sandy foreland that has grown outwards from the former coastline. But, whereas Morfa Dyffryn has large accumulations of shingle, Morfa Harlech possesses only one belt of I-mile or so which fringes the sand-dunes at the southern end of the triangle. The pebbles are large and travel gradually northwards. As there is no break between them and the shingle spit that goes north rom Mochras Island, it would be true to say that the shingle of Morfa Dyffryn and that of Morfa Harlech are continuous.
We shall find no more pebbles until we reach the southern coast of the Lleyn Peninsula, which points like a finger, 30 miles long, down the Irish Sea. The drift of the pebbles on this coast is, of course, eastward, yet the supply is scanty at the eastern end, the corner at which the southern coast of Caernarvonshire meets the coast of Merionethshire. There is very little shingle in the coves of Borth-y-Gest and next to none borders the hard, firm sands of Morfa Bychan, but beyond Graig Ddu (Black Rock), which is a small headland of dolerite, there is a substantial increase. The source of the pebbles is the boulder clay beneath Criccieth promenade and in the cliffs east of the town. A bank of shingle runs thence up to Graig Ddu. It has dammed up a former bay and turned it into a fresh-water lake, Llyn Ystumllyn.
Criccieth Castle stands on hard rock, called rhyolite (from a Greek word meaning ‘to flow’), of volcanic origin, containing the minerals, quartz and felspar. It was poured out on the surface in the form of lava.
The soft boulder clay then goes on westward to the headland of Pen-ychan. It provides numberless pebbles to form a belt of shingle from the promontory almost all the way to Criccieth. This shingle has pushed the mouth of the river Dwyfor eastward for a mile. The pebbles beyond Pen-ychan have been piled up by waves into high storm beaches. They remain in good supply for most of the way to Abererch, but diminish as we come nearer to Pwllheli. Behind the very pleasant beaches that lie to the west of that town is a layer of boulder clay, sand and gravel, but the headlands that separate the beaches are of hard, old rocks. Thus, Careg-yr-Imbill (Gimlet Rock), which protrudes between the two Pwllheli beaches, is a mass of dolerite, Careg-y-Defaid, the next headland to the west, consists of trachyte, a volcanic rock in which the principal mineral is a glassy kind of felspar, Llan-bedrog Mountain at the southern end of Llanbedrog Beach is a headland of porphyritic granite, and the two promontories of St. Tudwal’s Peninsula, Wylfa Head and Penkilan Head, consist of hard sandstone and flags. The three beaches of Llanbedrog,
Abersoch and Porth Caered are very attractive. Porth Caered contains the best shingle. The pebbles on all the beaches between Criccieth and St. Tudwal’s Peninsula are of interesting variety. having come from the generous supplies of boulder clay and the hard rocks of the headlands.
We turn to the north-west after rounding Penkilan Head and enter Hell’s Mouth or Porth Neigwl, a broad and pleasant bay that is not even remotely suggestive of eternal torment. Boulder-clay deposits of great thickness and a stretch of blown sand lie at the back of the beach. The softness of the bay is followed immediately by the hardness of the dolerite promontory to the west of it.
We are now near to Aberdaron Bay and the headland of Braich-y-Pwll, the ‘Land’s End’ of North Wales. Here begins a stretch of the most ancient rocks, extending for more than 12 miles with little interruption along the northern coast of the Lleyn Peninsula. The predominant rock in this section is pre-Cambrian schist, highly laminated, flaky, greyish-green in colour and beautifully lustrous when freshly broken. Dykes of dolerite have intruded here and there. There is little shingle along this aged and very rocky coast, but some very good pebbles lie on the two beaches of Nevin which are just beyond the pre-Cambrian rocks. Of the two beaches, Porth Dinlleyn and Porth Nevin, the former is the bigger and has more shingle. Cliffs of boulder clay rise at the back of each. The pebbles from these and from the ancient rocks to the south-west make up a goodly assortment. The longshore drifting along this coast is from south-west to north-east. Very little beach material from the south Caernarvonshire and Cardigan Bay coasts travels around Braich-y-Pwll, because the Lleyn Peninsula is such a formidable barrier. The headland to the west of Porth Dinlleyn, Careg Ddu (Black Rock), also impedes, but far less effectively, the movement of beach material up the coast. Careg Ddu consists of volcanic rock, mostly pillow-lava, which we last saw at Pentire Point in Cornwall. Steep cliffs with very little beach beneath them are the main feature of the coast beyond Nevin to the Trevor granite quarries. These are cut in the most seaward of the three high peaks of Yr Eifl (’The Rivals’ is an English mutilation of the Welsh name, but it is aptly descriptive of these peaks). Trevor granite is a beautiful stone and polishes well. Pebbles derived from it travel north-eastward up the Caernarvonshire coast.
The coast, up to Dinas Dinlle, near the south-western entrance to the Menai Straits, is almost wholly of boulder clay. It supplies pebbles in profusion to the belt of shingle that begins near Aber Desach and grows broader all the way to Dinas Dinlle. There it is piled up into a high storm beach. This ridge is the biggest on the northern coast of Caernarvonshire. Its pebbles, most of them extracted from the boulder clay, are also representative of the igneous, metamorphic and sedimentary rocks of the Lleyn Peninsula.
Leaving unexplored the rather muddy shores of the Menai Straits, we cross over to the south coast of Anglesey. This almost flat country appears featureless at first glance, but its coast is of charming variety and its rock structure is of bewildering complexity. The latter, indeed, is known to geologists as the Mona Complex (Mona being the Roman name of Anglesey). Much of its rock is pre-Cambrian and it has been so folded, crushed and sheared as to make the task of discovering the original stratification supremely difficult. The coastal rock pattern is too intricate to be unfolded here in any detail. We shall consider only the main features.
Longshore drifting from the Menai Straits up to Holy Island follows the north-western direction of the coast. Newborough Warren is a broad expanse of sand-dunes bordered with a little shingle, to which the pillow-lava, jasper and green schist of Llanddwyn Island make an agreeably coloured contribution. This side of Anglesey, especially Malldraeth Bay and Aberffraw Bay, is extremely sandy. We find little shingle until we reach Rhosneigr and Cymmyran Bay, where the sandy coast, especially of the bay, has a long belt of pebbles. They come from the boulder clay and from the rocks of mica schist, granite, sandstone, dolerite, gabbro and serpentine. The two last outcrop near the shores of the Strait that separates Holy Island from Anglesey. The serpentine is of the green variety, with a glossy surface and silky to the touch, but the weathered pebbles are dull. After the removal of the ‘skin’ and a little polishing, they display their true and lovely colouring.
The two best beaches on Holy Island itself are Borth Wen (Rhoscolyn) and Trearddur Bay, though neither possesses extensive shingle. The pebbles mostly come from the three main rocks that compose the island: mica schist, Holyhead quartzite and very hard, grey grit, all of them pre-Cambrian. The rocks of Newry Beach, Holyhead, are all of mica schist, but the beach is covered with fragments of the local quartzite, dumped there during the building of the breakwater in the middle of the last century. These fragments have not even yet been smoothed and rounded into true pebbles.
On the west coast of Anglesey the best bed of shingle is in the Porth Swtan end of Church Bay, where there are high cliffs of boulder clay from which the beach receives a large and varied quota. Rocks of pale yellow volcanic tuff, lying beneath the boulder clay, and adjacent strata of hard, dark grit (Skerries grit) and green schist also contribute their share. A few pebbles of jasper can usually be spotted by the patient collector.
The north coast has comparatively little shingle, but there is one good ridge I-mile long, banked up high above the arc of Cemlyn Bay. This is a storm beach inasmuch as it is the product of exceptional violence: that of 26th October 1859, which wrecked the Royal Charter at Moelfre with the loss of 455 lives. The ridge has produced the effect of a natural dam, for a lagoon now lies behind it, falling and rising with the tides. The top of the shingle ridge is about 20 feet above the high-water mark of the lagoon. Cemaes Bay shingle yields purple jasper.
Red Wharf Bay on the north-east coast is a very large expanse of slightly reddish sand. Its shingle is mostly drawn from the limestone cliffs to the west of it and from the eastward drifting pebbles formed from the granite, green schist and mica schist of the north-east Anglesey coast. There is also a fairly plentiful supply of chert from the limestone.
Coming back to Carnarvonshire again across the northeastern entrance to the Menai Straits, we must go on to the beaches of Llanfairfechan and Penmaenmawr to find any shingle deserving of comment. Rocks of the Ordovician Age, shales, grits and slates lie behind the beaches, but Penmaenmawr Mountain is a huge mass of igneous rock, diorite, which is used largely for road metal and railway-track ballast. It is a very hard and close-grained stone of greyish-blue. Some large amount has made its way to the beach during the loading of ships at the quarry quays and has been rolled and rounded into pebbles. The shingle of the Penmaenmawr beach lines the coast up to the flat plain of Conway Morfa, the sand and alluvium of the Conway estuary, now largely grass-covered. Beyond the estuary is the Creuddyn Peninsula, a foreland terminating in two bold headlands, the Great Orme and the Little Orme, with the seaside resort of Llandudno lying between them. Both of these headlands consist of limestone. The Great Orme, thrusting itself far out to sea, acts as a great groyne against the eastward drifting of the Anglesey and North Carnarvonshire pebbles. Llandudno has two beaches: the West shore facing Anglesey and the beach between the two Ormes facing north. The former is of sand, which at low water seems to stretch out far to the south-west. It must have been here that
The Walrus and the Carpenter were walking close at hand and wept like anything to see such quantities of sand for Lewis Carroll stayed at the Gogarth Abbey Hotel on this shore and roamed about it with little Alice Liddell, the original ‘Alice’.
The shingle of the other beach has many pebbles of Great Orme limestone, with some of grit, shale, slate, diorite, etc., that have contrived to make their way round from the other side of Conway Morfa.
Limestone pebbles from the Little Orme feed the beaches of Rhos-on-Sea and Colwyn Bay. The long promenade now protects the cliffs of boulder clay between those two places. Before it was built, there was considerable erosion and a wealth of pebbles was washed out from the clay. The promenade now reaches to Old Colwyn, so the Colwyn Bay shingle is not as plentiful as it once was. However, it is still fairly extensive and is varied enough to be interesting. Limestone, of course, is the main contributory, but there are still many boulder-clay pebbles left, including some good specimens of quartz. At the east end of the bay is another limestone headland, Penmaen Head, from which pebbles of that rock travel eastward to add to the beach material of Llandulas and Abergele. Boulder clay to a great depth lies between these beaches and the hills inland, so there is no shortage of shingle. Together with the sand from the dunes on the shore between Abergele and Rhyl it has deflected, by eastward drifting, the mouth of the river Clywd one mile to the east. Groynes at Prestatyn check the drifting to some extent and help to deepen the beach there. The drifting comes to an end in the high storm ridges off the Point of Air.
And here we almost come to the end of our quest for pebbles on the west coast. The Point of Air marks the eastern end of the great estuary of the river Dee. On the Welsh side there are mudflats, marshes and alluvium all the way. The shores of the Wirral Peninsula on the other side are more refreshing. A boulder-clay cliff runs behind them as far as West Kirby and provides shingle between Neston and West Kirby. The great dunes of Hoylake and Wallasey are the main feature of the north coast of the peninsula, but we have far to go before we come upon any extensive beds of shingle. Quickly passing the Mersey estuary and the completely industrialized coast of the Liverpool area, whence runs a long coast of sand-dunes to Southport, we come to the peat of the Ribble estuary. There is some shingle on its northern shore. It has drifted from the beaches on the south of Blackpool along the shore of St. Anne’s towards the salt-marshes of Lytham and beyond. In doing this the pebbles from the coast immediately south of Blackpool have, for a reason yet to be discovered, broken the general rule of longshore drifting on the west coast. The shingle comes to an end at South Shore. The Blackpool beach between South and North Shore is wholly of sand. Then the shingle begins again and increases in extent as we get near to Cleveleys. The supply from there to Fleetwood is bountiful. Most of the pebbles come from the boulder-clay cliffs that form the Lancashire coastline north of Blackpool. They contain some pebbles brought down by glaciers from the Cumberland and Westmorland mountains, so much of the shingle is of grit, limestone, sandstone and granite and other igneous rocks.
The coast makes a turn to the right before we reach Fleetwood, which stands at the entrance to the Wyre estuary. The river runs out between mud-banks and salt-marshes. So far all the coast of Lancashire has been bounded by soft material: boulder clay, dunes and marsh, except, of course, where man has built sea-walls and promenades. The first outcrop of solid rock that we come to all the way from the Mersey is some red sandstone at Cockersand Abbey, south of the Lune estuary, and here there is a good shingle beach. We are now within sight of More-cambe Bay. In one respect this large bay resembles the Wash: on some of its long coast the distance between high- and low-water marks is several miles. There are great expanses of sand and silt and there is a large spread and depth of boulder clay. To find shingle beds we must pass across the bay to Walney Island.
This 8-mile-long and narrow island that provides a natural breakwater for the protection of Barrow-in-Furness must have come into existence when the glaciers on this part of the coast melted, for it consists of boulder clay, sand and gravel. There is glacial shingle on its beaches and ridges of that shingle extend from its northern and southern ends. Of the four islands to the east of Walney, Sheep, Roa and Foulney are all composed of shingle, and Piel is almost all shingle. The exception to the general rule about longshore drifting on the west coast begins to apply at Walney Island. From St. Bees Head to the island the drifting is southward.
Great spreads of sand, the Duddon Sands, lie north of Walney Island at the broad mouth of the river Duddon. The seemingly endless boulder clay goes on and on, but it has one interruption at Holbarrow Point at the entrance to the estuary. It is an outcrop of limestone. The pebbles from the boulder clay have planed down the rock to a smooth platform here by their rolling. When we have crossed the estuary our course lies along a smooth, flat coast, only slightly indented. It is lined with cliffs of boulder clay. Sand and sand-dunes increase as we approach Eskmeals. There is a narrow estuary to the north of Eskmeals through which the three rivers, Esk, Mite and Irt, all come out to sea. The outflow of the Irt is turned 2 miles to the south-east by a long and wide spit of sand and shingle, called Drigg Point. Nearly all the pebbles have come from the boulder clay. For the next 4 miles, to Seascale, there is nothing but sand and dunes lining a dead straight coast, but a mile or so beyond Seascale we come to another joint river mouth, that of the Calder and the Ehen. A spit of shingle surmounted by sand-dunes keeps the Ehen inshore for a distance of 2 miles until it is forced to join the Calder.
The straight coast of low cliffs of boulder clay continues to St. Bees Head. At long last we see high cliffs of solid rock. There are two points to remember about St. Bees Head. It is the first promontory of high solid rock north of Penmaen Head at Colwyn Bay; and it marks the point at which the northward drifting of beach material up the west coast starts again. The fine cliffs of St. Bees Head are of hard red sandstone. Other good cliffs of hard limestone follow on as far as Saltom Bay. The cliff line is lowered to beach level only in Fleswick Bay. Here is a pebble beach on which the collector should linger, for among its pebbles of limestone, sandstone and shale from the local rocks are many from the boulder clay, brought down by the glaciers of Cumber- land and south-west Scotland. These include numerous pebbles of igneous rock and quartz in several of its chalcedonic varieties. Some good specimens of agate, jasper and carnelian can be found. This beach deserves all the attention we can give to it, because it is also the last shingle deposit of interest to the collector on this coast. The shore from Whitehaven Harbour to Maryport is blackened by slag heaps, mine-refuse dumps, drifting coal-dust and pebbles of blast-furnace slag. Owing to the northward drift this rubbish travels as far as the Solway shore. The last miles of our tour are along a low, flat coast of boulder clay fringed here and there by dunes, sand-hills, marshes, alluvium and peat-bogs. There are a few ridges of shingle and boulders, but the only interesting features are the sections of raised beach. These are prominent to the north of Workington, Allonby and Beckfoot. Indeed, raised beach deposits are visible almost all the way from Workington to Beckfoot, running parallel with the present-day beach and touching it at those points where there are high storm beaches. We find the raised beach again near Beckfoot, whence it goes on through Silloth to Grune Point on the far side of Skinburness Marsh. As we enter the narrow and inner part of the Solway Firth we find it between Anthorn and Bowness. For most of their course the raised beaches are elevated about 14-15 feet above the modern beaches, but at Grune Point the shingle of the raised beach is actually growing with some rapidity as the result of longshore drifting.