520 RECENT. 



etc. ; also many land and fresh-water Mollusca,^ including Unio littoralis, var. 

 These remains occurred in beds of fine sand overlaid by gravel, 8 feet thick. 



The valley gravels at Charmouth, near Lyme Regis, near Bridport, at Burton 

 Bradstock and Loders have yielded remains of Mammoth ; at Lyme the Rhinoceros 

 has also been found, and at Motcomb the Hippopotamus.^ 



At Kentisbere a Palaeolithic implement has been found by the Rev. W. Downes,* 

 and a short time previously many specimens, fashioned out of Greensand chert, 

 were obtained by Mr. W. S. M. D'Urban in a large ballast-pit in the Axe valley 

 at Broom, not far from Hawkchurch, near Axminster.* Here there is nearly 

 30 feet of gravel. 



There are many valley deposits whose age is uncertain, no Pleistocene Mammalia 

 or other organic remains having been found in them. 



The valley deposits of the Taff, Rhondda, and Cynon in Glamorganshire, have 

 been described by Mr. A. Tylor.* Li the neighbourhood of Hereford there are 

 extensive beds of valley gravel in places 30 feet thick and 15S feet above sea-level.'' 

 (See Fig. 15, p. 105, and p. 493.) 



The gravels of the Dart above Totnes have been described by INIr. Ussher. 

 They contain large boulders of granite, quartz, grit, etc.: the absence of Cretaceous 

 materials is noteworthy. At Holne Chase the river has excavated a gorge 60 feet 

 or more in depth. These accumulations suggest a greater volume of water in 

 former times than is now carried down V)y the river.' 



In the Chalk districts of the east of England there are accumulations of gravel, 

 chiefly made up of subangular and partially rolled flints, which occur in dry 

 valleys : hence the beds are sometimes termed Dry-valley gravel. Beds of this 

 character occur near Great Marlow and Henley-on-Thames, in Buckinghamshire, 

 and they often merge into the Thames valley-gravels, although they are chiefly due 

 to the direct subaerial waste in the Chalk combes. In Yorkshire the dry Chalk 

 valleys north-west of Bridlington, near Weaverthorpe, Foxholes, and other places, 

 contain gravel, sometimes 40 feet thick. 



Recent Alluvial Deposits. 



Under this heading we have grouped for the sake of convenience 

 all the Modern accumulations of our river-valleys, including not 

 merely the Alluvium, but also the Lacustrine deposits, Peat-beds 

 and Submerged Forests, and the Estuarine Scrobicidaria-cX^.y's,. The 

 deposits contain remains of Mammalia now existing in this country, 

 or but recently exterminated from it,* as well as other organic 

 remains belonging to species still living in England. (See p. 478.) 

 They indicate some oscillations in the level of the land, as for 

 instance in the succession of deposits met with in Porlock Bay. 



Alluvium. — Those who wander along the banks of our rivers will 

 observe the flats of marsh or meadow land that usually flank them, 

 bordered now on one side, now on the other by a cliff, and marked 

 off from the surrounding country which rises gently or abruptly 



1 Mem. II. E. Strickland, by Sir W. Jardine, 1S58, pp. clxiv, 79, 95 ; Proc. 

 G. S. ii. 9S, III ; Hull, Geol. Cheltenham, p. 85 ; W. S. Symonds, G. Mag. 

 1868, p. 413 ; T. G. B. Lloyd, Q. J. xxvi. 202. 



* T. Thompson, G. Mag. 1869, p. 206. 

 3 G. Mag. 1879, p. 480. 



* G. Mag. 1878, p. 37 ; Evans, Journ. Anthrop. Inst. vii. 499. 



5 Q. J. XXV. 66. 



6 T. Curley, Q.J. xix. 175. 



' Ussher, Trans. Devon. Assoc. 1876. 



^ J. E. Harting, British Animals extinct within Historic Times, 1880. 



