matter. The stratum has been traced seaward as far as the ebb permits, and it implies the downward movement of a level tract which preserved its horizontality when subsiding. If we endeavour to form a conjecture as to the probable date of such a submergence, we find ourselves involved in a geological enquiry of vast extent, although so modern as to be comprised within the human period. Thus at Torquay in Devonshire, there is a submerged forest, and much peaty matter resting on bluish clay, which may be traced from the neighbourhood of Tor Abbey, at a height of about eightyfour feet above the sea, for three quarters of a mile to the shore. The same bed extends to an unknown distance seaward, many stumps and roots of trees being observed firmly fixed in the clay, and in the peat, bones of the deer, wildhog, horse, and the extinct Bos longifrons occurring; with these, the antler of a red-deer was observed by Mr. Pengelly, having several cuts on it made by a sharp instrument, and the whole fashioned into a tool for piercing. From this forest-bed, at a point in the bay where there is a depth of more than thirty feet of water, the fishermen drew up in their trawl, a few years before 1851, the molar tooth of the mammoth, or Elephas primigenius, stained with the black colour of the peat, and retaining much of its animal matter, its fresh condition being probably due to the antiseptic quality of the peat. The specimen is now in the Torquay museum, and it is interesting as serving to establish the fact, that the mammoth survived when the surface of this region had already acquired its present configuration, so far as relates to the direction and depth of the valleys in the bottom of one of which the peat alluded to was formed. I mention these facts to show that submarine forests on this coast cannot be safely appealed to in confirmation of changes which may have occurred in the historical period. They may belong to the close of the paleolithic era, although long subsequent to the filling of the caves of Brixham and Kent's Hole, near Torquay, when the elephant, rhinoceros, and cave-bear coexisted with man, before the excavation of some of the valleys which now descend to the sea on this coast. To return to Cornwall: the oldest historians mention a tradition of the submersion of the Lionnesse, a country said to have stretched from the Land's End to the Scilly Islands. The tract, if it ever existed, must have been thirty miles in length, and perhaps ten in breadth. The land now remaining on either side is from two hundred to three hundred feet high; the intervening sea about three hundred feet deep. Although there is no authentic evidence for this romantic tale, it probably originated in some former inroads of the Atlantic, accompanying, perhaps, a subsidence of land on this coast. If we then turn to the Bristol Channel, we find that both on the north and south sides of it there are numerous remains of submerged forests; to one of these at Porlock Bay, on the coast of Somersetshire, Mr. Godwin-Austen has lately called particular attention, and has shown that it extends far from the land. There is indeed good reason to believe that there was once a woodland tract uniting Somersetshire and Wales, through the middle of which the ancient Severn flowed. The former existence of such land enables us to comprehend how along the southern coast of Glamorganshire fissures and caves in the face of precipitous cliffs at the base of which the sea now beats, may have been frequented by the elephant, rhinoceros, bear, tiger, hyena, and other quadrupeds, most of them now extinct. At St. Bride's Bay, in Pembrokeshire, and proceeding farther to the north in Cardiganshire and again in North Wales, (as in Anglesea and Denbighshire,) we have repetitions of the same appearances of ancient forests adjoining the coast. One of these in Anglesea reminds us in a striking manner of the phenomena before mentioned as characterising the forest-bed of Tor Abbey. A bed of peat three feet thick, with the stumps and roots of trees, was observed by the Honourable W. Stanley, exposed at low water in the harbour of Holyhead, and stretching upwards to a slight elevation above the sea, where the excavations made for the railway in 1849 brought to light two perfect heads of the mammoth. Its tusks and molars lay two feet below the surface in the VOL. I. * Memoir read Nov. 1865. Geol. Proc. N N peat, which was covered by the stiff blue clay.* It is not improbable that this mammoth survived most of the lost species which were its contemporaries in what has been called the Cavern period. At the same time, we must not forget that the fauna, not only of the bronze age, but of the oldest lake-dwellers of Switzerland to whom the use of metals was unknown, was identical with that of the historical era, no mixture of the bones of the mammoth or of Bos longifrons, or even of the reindeer, having been detected, whether among the wild or domestic animals of the lacustrine habitations of Switzerland or in the kitchen-middens of Denmark. If, therefore, all the littoral, sunk forests of the south and west of England are referable to about the same geological period, the occasional presence in them of the mammoth will entitle them to be regarded as very ancient, or of a date intervening between the era of the lake-dwellings and that of the oldest epoch to which man has yet been traced back. West coast of England.—Having now brought together an ample body of proofs of the destructive operations of the waves, tides, and currents, on our eastern and southern shores, it will be unnecessary to enter into details of changes on the western coast, for they present merely a repetition of the same phenomena, and in general on an inferior scale. On the borders of the estuary of the Severn the flats of Somersetshire and Gloucestershire have received enormous accessions, while, on the other hand, the coast of Cheshire, between the rivers Mersey and Dee, has lost, since the year 1764, many hundred yards, and some affirm more than half a mile, by the advance of the sea upon the abrupt cliffs of red clay and marls. Within the period above mentioned several lighthouses have been successively abandoned.† There are traditions in Pembrokeshire and Cardiganshire§ of far greater losses of territory than that which the Lionnesse tale of Cornwall pretends to commemorate. They are all impor * One of these skulls, referred by Prof. Owen to Elephas Primigenius, has been presented to the British Museum by the Hon. W. Stanley, M.P., on whose property they were found. + Stevenson, Jameson's Ed. New Phil. Journ. No. 8. p. 386. Camden, who cites Gyraldus; also Ray, On the Deluge,' Phys. Theol., p. 228. § Meyrick's Cardigan. tant, as demonstrating that the earliest inhabitants were familiar with the phenomenon of incursions of the sea. Loss of land on the coast of France.-The French coast, particularly that of Brittany, where the tides rise to an extraordinary height, is the constant prey of the waves. In the ninth century many villages and woods are reported to have been carried away, the coast undergoing great change, whereby the hill of St. Michael was detached from the mainland. The parish of Bourgneuf, and several others in that neighbourhood, were overflowed in the year 1500. In 1735, during a great storm, the ruins of Palnel were seen uncovered in the sea.* * Von Hoff, Geschichte, &c. vol. i. p. 49, 548 CHAPTER XXI. ACTION OF TIDES AND CURRENTS-continued. INROADS OF THE SEA AT THE MOUTHS OF THE RHINE IN HOLLAND CHANGES TERRANEAN. Inroads of the sea at the mouths of the Rhine.-THE line of British coast considered in the preceding chapter offered no example of the conflict of two great antagonist forces; the influx, on the one hand, of a river draining a large continent, and, on the other, the action of the waves, tides, and currents of the ocean. But when we pass over by the Straits of Dover to the Continent, and proceed north-eastwards, we find an admirable illustration of such a contest, where the ocean and the Rhine are opposed to each other, each disputing the ground now occupied by Holland; the one striving to shape out an estuary, the other to form a delta. There was evidently a period when the river obtained the ascendancy, when the shape and perhaps the relative level of the coast and set of the tides were very different; but for the last two thousand years, during which man has witnessed and actively participated in the struggle, the result has been in favour of the ocean; the area of the whole territory having become more and more circumscribed; natural and artificial barriers have given way, one after another; and many 1 |