334 



upon the surface of the gravel and sandj but cuts which have beea 

 made through mounds of these materials at Norton, near Shrewsbury, 

 have proved that the larger blocks occur at considerable depths 

 below the surface mixed up with shells, sand, gravel, and clay. This 

 is the locality described by Mr. Trimmer* as indicating the exist- 

 ence of dry land anterior to the deposit of the shells and gravel, by 

 the occurrence of a peat bog, which he supposed to have been formed 

 out of the remains of a submerged forest ; the stumps of the trees of 

 which were said to be still rooted in their parent soil, and standing in 

 their growing posture. Having examined the spot (accompanied by 

 Dr. Du Gard), Mr. Murchison has obtained clear proofs that the sup- 

 posed trees were stakes with sharpened points which had been driven 

 down into a patch of subjacent clay ; the other remains consisting of 

 a plank and smaller stakes which had been laid horizontally. This 

 woodwork formed the support of the old road, which in making the new 

 one had been cut down beneath the ancient foundations. The 

 patch of clay into which the piles were driven, lying in a depression 

 between two hillocks of gravel, must have given rise to a wet and 

 boggy spot, which having been rendered passable by piling and dam- 

 ming, the dry materials of the contiguous hillocks were doubtless 

 shovelled in to complete the road, thus giving rise to the deceptive 

 appearances of marine drift overlying the supposed forest. 



Though the collocation of the boulders, sand, gravel, loam, clay, and 

 shells is in parts very irregular, yet the materials are sometimes finely 

 laminated : the whole, it is presumed, may have been thus brought 

 together at the bottom of a sea, as the mass is not unlike many raised 

 sea-beaches, with one of which, at the mouth of Carlingford Bay, Ire- 

 land, recently visited by Professor Sedgwick and himself, the author 

 compares it. 



From the evidences afforded by these recent shells it is inferred, that 

 the tracts covered by them must have lain under the sea during the 

 modern period ; whilst from the continuation of the granitic drift 

 from the high grounds east of Bridgnorth into the Vale of Worcester, 

 Mr. Murchison conceives that the sea must at the same time have 

 covered the Valley of the Severn from Bridgnorth to the Bristol 

 Channel, thus separating Wales and Siluria on one side, from En- 

 gland on the other. Having shown that the Welsh and Silurian 

 mountains were partly raised at an earlier period, he points out the 

 Abberley and Malvern Hills, as constituting the western side of a 

 strait of the sea, the eastern shore of which was the Cotteswold Hills. 

 He deduces the principal proof of the preexistence of this eastern 

 coast from the observations of Mr. H. Strickland, which show the 

 transport from the east and north-east of fiuviatile and land shells 

 mixed with the remains of extinct quadrupeds in banks of coarse 

 gravel, following the drainage of the Avon near to where that river 

 empties itself into the Severn ; and he asserts, that the terrace-like 

 deposits of Cropthorne are exactly those which would have been ac- 

 cumulated at the mouth of a river, if the materials had been carried 

 onwards beneath the waters of the adjoining strait of the sea, illus-. 

 * Proceedings of the Geological Society, Vol. II. p. 200. 



