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Between Watchet and Blue Anchor Head the low-water shore dries out half a mile and is rocky, beyond which the beach is covered with large boulders and coarse sand. In the bight west of Blue Anchor to Minehead the coast is low, the beach being from 7 to 10 feet above low water.
West of Minehead the rocks approach nearer the sea, and there is very little beach except in the bights of the bays. The coast for 4 miles is rocky, with shallow water extending out from the cliffs for half a mile, the bottom being covered with boulders and rocky spits.
Porlock Bay lies recessed between Hurtstone Point (which consists of quartzose sandstone) and Gore Point. The beach is covered with boulders and shingle composed of greywacke and other local rocks, and beyond these is a considerable area of sand.
From Porlock to Lynton the sandstone cliffs, which are 1100 feet high, descend to the water without any beach. West of Foreland Point, which consists of hard quartzose sandstone, is the harbour of Lymouth, which lies in the valley of the West Lynn River. The shore, which is recessed from the cliffs, is a mile in length, and is fronted by a mass of large boulders which dry at low water for a quarter of a mile. The harbour is protected by a ridge of gravel and sand a mile long and 250 yards wide, which lies parallel with the coast at a distance of a quarter of a mile seaward. The highest part of this ridge is bared at very low tides, and between it and the shore is a depth of 7 fathoms. The tide runs from 4 to 5 knots past this ridge.
From Lynmouth to Bull Point the coast continues rocky, and the cliffs, which rise from 1100 to 1200 feet, are steep, with occasional breaks as at Martinhoe and Combe Martin Bay. At Watermouth is a sandy cove. The harbour at Ilfracombe, 6 acres in extent, lies in the break between Lantern Hill and Capston Hill. Helesborough Cliff on the east is 420 feet high, and is fronted by rocks dry at low water for a distance of 200 yards. Beyond Ilfracombe the coast is bordered by high cliffs which are intersected by Lee Bay.
Morte Bay lies to the south beyond the western point of the shore of the Bristol Channel, and has a clear fetch to the southern coast of Ireland. It is 24 miles wide, and is recessed between Morte and Baggy Points 2 miles, the former consisting of slate rock with beds of quartz, and the latter of hard greywacke sandstone. It has a good sandy beach a quarter of a mile wide. Barricane Beach is covered with sand composed of sea-shells.
Barnstaple Bay.-On the west side of Baggy Point lies Barnstaple Bay, which is bounded at its southern extremity by Hartland Point, a precipitous rocky cliff of hard carboniferous sandstone and shale 350 feet above the sea. The sea is wasting this cliff. The bay faces north-west, and is exposed to the full fetch of the Atlantic, the waves in north-west gales breaking on the shore with tremendous force. Spring tides rise 27 feet, and the flood tide sets along the shore first eastward and then north-easterly. The southern side of the bay is faced by cliffs as far as Rocks Nose, a little south of Westward Ho. In a break in these cliffs is situated the little harbour of Clovelly. The cliffs gradually die out to the sands and low ground on the north, which form the estuary of the rivers Taw and Torridge. The whole of this foreshore is skirted by large boulders, terminating beyond the cliffs in the remarkable pebble ridge, of which a separate description is given.
Inland, to the north of the river Taw is a large tract of sandhills a mile in width, known as Braunton Burrows, terminating in Down Hill, 2% miles to the north. The sand-hills continue on from the north side of the Down End along the south-west side of Croyde Bay.
The Northam Pebble Ridge.—This accumulation of large boulders and shingle, forming a bank over 2 miles in length, is composed of the material eroded by the action of the waves, which break with great force on the cliffs extending along the southern side of Barnstaple Bay from Hartland Point to Rocks Nose, a distance of 13 miles. These cliffs rise to a height of over 350 feet, and consist of hard carboniferous grit of a dark slate colour, except at the western end, where this rock is interspersed with red sandstone and shale and a few pockets of glacial drift. The beach between the foot of the cliffs and low water consists of rocks cut and furrowed by the action of the sea in perpetually rolling about the large boulders which lie along its surface.
Large fragments of rocks have in the course of ages been dislodged from the cliffs, the remains of which, perpetually rolled about by the waves of the sea during high tides, which here rise to a height of 27 feet, have acted as instruments for grinding their fellows, and battering the cliffs, and so producing the rounded boulders which now strew the beach throughout its whole length for several miles, and a portion of which, drifted along the shore of the bay, has become finally heaped up in the Northam pebble ridge.
In some parts of the cliff indents of considerable size have been cut out, and across these the boulders have collected, and been thrown up into ridges and banks. At Abbotsham, about 12 miles from Hartland, there is such a bank, the top of which is 9 feet above high water of spring tides. This ridge or bank is about 160 feet wide, the boulders of which it is composed varying in size at the top from about 12 inches in length by 4 inches in diameter to pebbles 3 inches in diameter, the largest boulders weighing about 12 lbs., those at the foot reaching to a length of 2 feet and weighing about 70 lbs. Notwithstanding the large size of the boulders of which the bank is composed, its sea face is shaped into a ridge and hollow, similar to other pebble ridges, the position of which varies according to the height of previous spring tides. The pebbles left on the shelf or hollow at the spring-tide level are of a smaller size than those at the other part of the bank.
The boulders scattered along the beach all lie above the level of low water of neap tides. The general direction of movement is eastwards, but the boulders follow the line of the coast and the set of the flood tide. This direction varies round the bay from eastward to south-east, east again and then north-east, and finally south-east. The direction of the wind which drives the heaviest sea into the bay is from the north-west.
The Northam pebble ridge commences at the termination of the cliffs, and runs in a north-north-easterly direction for upwards of 2 miles across a low flat plain, which is below the level of high tides, until it falls into some hummocks of blown sand. It thus forms a natural embankment enclosing a tract of 900 acres of sandy and alluvial grass land, which is used for grazing purposes and also as golf links. After running along the foot of the sandhills for a short distance, the pebble bank turns sharply to the south-east up the course of the outfall of the two rivers, the boulders diminishing in size to pebbles and coarse sand. There is an outlying bed of boulders, known as the Pulley, situated some distance from the bank, on the edge of the low-water channel of the river; but these appear to be a fixed deposit, which neither increases nor diminishes in size.
The ridge is approximately 180 feet wide at the base and 20
feet high, the top being about 25 to 30 feet wide and 6 feet above high water of spring tides. The boulders on the top of the bank vary in size from 12 inches in length by 6 inches in diameter to pebbles 1 inch in diameter, the average size being about 8 inches in length by 4 inches in diameter, the largest being 12 inches long and weighing from 40 to 50 lbs. At the foot of the bank are to be found boulders measuring from 15 to 18 inches in length and weighing from 100 to 150 lbs. The size of the boulders does not vary much throughout the length of the bank. The greatest collection of small stones appears to be on the shelf or hollow at the level of spring tides, where the pebbles vary from } inch to 4 inches in diameter. Some of the larger boulders have been drifted quite to the far end of the bank.
The boulders consist entirely of the same description of slatecoloured carboniferous grit as the cliffs from Hartland to Abbotsham are composed of, and there can be no doubt that they have drifted from this part of the coast. At the commencement of the ridge there are fairly numerous samples of shale and red sandstone pebbles from the cliffs between Westward Ho and Abbotsham, but these gradually disappear further along the ridge, the softer rock of which they are composed evidently not being able to withstand the constant grinding process produced by the wave-action of the tides and wind. From the foot of the bank to low water the beach is covered with sand, which dries from a third of a mile at the south end to three-quarters of a mile at the northern end.
There is a very slow but continuous drift or movement of the boulders along the bank northwards. The progress of the ridge being stopped by the sand-hills, the bank has bifurcated at this point, a new or double bank now forming, a circumstance which has occurred within the knowledge of those who have known the bank all their lives.
The boulders composing the ridge are in perpetual motion during the time that the bank is covered by the sea at spring tides. Even in calm weather in summer the whole face of the bank is continually changing under the influence of the wave-action of the flood and ebb-tide, which is of sufficient force to cause the movement of the large boulders. Observers who have carefully watched this movement and marked individual stones, find that they are never in the same place two tides running, and each spring tide leaves its impress in a hollow and ridge at high-water mark.
In heavy on-shore gales these ridges and hollows are obliterated, and the face of the bank is pulled down seaward, the extent to which this is carried depending on the force and duration of the gale. After the storm, and when the height and force of the waves have subsided, the pebbles begin to move back again; the contour of the bank becomes more steep, and is soon restored to its normal condition.
During the winter at the end of 1896 there was a succession of westerly gales, culminating in a very heavy storm from the northwest. The bank was torn down and so lowered that the waves broke over it and inundated the enclosed land. Some of the largest boulders were thrown over the top of the ridge and hurled a considerable distance inland, where they remain as a witness to the force of the gale. The disturbance of the boulders was so great under the action of the waves, that after the gale it was found that the base of the bank was moved 10 yards inland, the clay bed on which it had rested previously being exposed. A somewhat similar movement took place during a gale about twenty years previously.
The peculiarity of this pebble ridge, and the way in which it differs from ordinary shingle-banks, is in the large size of the boulders drifted along the coast, and heaped up by the action of the waves and tides.
The action of the waves on this bank has been graphically depicted by Charles Kingsley in “ Westward Ho,” where he describes the sea as having defeated its own fury by rolling up, in the course of ages, a rampart for the protection of the land at the back, on which the waves, breaking at high water and continually rolling the boulders up and down its sea slope, cause a loud murmur which may be heard at a considerable distance; but when the mighty surges due to a ground swell rolling in from the ocean break on the bank, this murmur increases to a loud roar, “the everlasting thunder of the long Atlantic swell.” This is frequently the harbinger of a coming storm, when the sea breaks on the shore with all the fury due to a heavy onshore gale, and then it is that the advancing waves hurl some of the boulders up the slope, throwing them over the top of the bank for a considerable distance on to land at the back, while others, rattling down the face of the bank with each retreating wave, create a deafening roar, which may be heard several miles inland.