Vol. 52.] MAMMALIAN REMAINS IN DERWENT RIVER-GRAVELS. 501 



Part II.— By R. M. Deelev, Esq., F.G.S. 



The deposits in and beneath which the mammalian remains were 

 fouud occur on the inside edge of a gravel-terrace which covers a 

 large area on the right side of the Derwent Yalley below Derby. 

 Its south-western boundary is more or less obscured by a variable 

 thickness of unstratified, yellow, sandy clay containing pebbles. 

 Masses of this pebbly deposit frequently penetrate 6 or 8 feet 

 into the gravel, much as does the 'trail' of Southern England. 

 At its inner edge the gravel terminates against rising ground, 

 composed of Keuper Marl capped in places by Boulder Clay. The 

 line of junction between the gravel and the Keuper commences on the 

 south side of the breach made in the Derwent Valley escarpment by 

 the Kedleston Brook. Erom here it skirts the lower portion of the 

 Royal Infirmary grounds, crosses the railway near Osmaston Road, 

 passes a few yards to the south-west of the section at Allenton, 

 and then skirts the base of Chellaston Hill until the river-escarp- 

 ment of the Trent, a mile north of Aston-on-Trent, is reached. Its 

 north-eastern boundary is a continuous and steep escarpment about 

 18 feet above the modern alluvial plain of the Derwent. 



This escarpment, starting near the Kedleston Brook breach, 

 passes through the Midland Railway-station, and keeping on the 

 north side of the London road, passes through Alvaston, Elvaston, 

 and Aston, w 7 hen it joins the corresponding escarpment of the 

 Trent Yalley. 



Over the whole of this area the terrace is nearly flat, and slopes 

 gently down the valley and towards the river. It is drained by two 

 small streams, the larger of which rises near the spot where the 

 bones were discovered. The point where the bones were found is 

 indicated by a circle on the map, fig. 2 facing p. 502. 



This portion of the ground I have contoured, so as to show the 

 exact relationship between the Boulder Clay capping the ridge, the 

 Derwent gravel to the N.E., and the low-level deposits of Sinfin 

 Moor to the S.W. As the line of demarcation between the gravel, 

 Keuper Marl, and Boulder Clay is more or less obscured by a sheet 

 of ' trail,' the line marking the edge of the gravel is only approxi- 

 mately correct. The outcrops were, however, carefully followed by 

 means of a boring-rod. The Boulder Clay was found to rest in all 

 places upon Keuper Marl. It is a tough, bluish, sandy clay, with 

 numerous striated limestone-boulders, and an abundance of coal, 

 shale, gritstone, etc. 



The gravel below the deposits in which the bones were found does 

 not, therefore, either rest upon or pass beneath the Boulder Clay, but 

 terminates rather abruptly against Keuper Marl. 



A map published in this Journal, vol. xlii., p. 438, shows the whole 

 of the terrace and also the surrounding deposits. 



Fig. 3 (p. 502) is a section passing through the Allenton terrace. 

 It commences in post-Glacial Trent Gravel, and then passes through 

 High-level Trent Gravel, Sinfin Moor deposits, Pennine Boulder 



