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Conspicuous by their presence in the above list are firstly 

 the Mammalian remains which indicate considerable antiquity ; 

 Elephas antiquus is, I believe, only known by a single tooth, and 

 it has been suggested that this may have been derived from 

 some older gravels; secondly, the occurrence of Cyrena Jiuminalis, 

 Unio littoralis and Hydrobia marginata must be noted, as they 

 are all now extinct in Britain. 



Conspicuous by their absence are Unio tumidus, Neritina 

 Jluviatilis, Paludina Listeri and Lymncea stagnalis, since all 

 these are now common in the Cam and its alluvium, associated 

 with most of the other freshwater shells named in the above list; 

 the former two however are generally found in the full strength 

 of the current, while the latter two prefer stagnant marsh pools; 

 but this is hardly sufficient to account for their total absence 

 (even as drifted shells) in the Barnwell sand. 



Gravel is found behind the wall of the old Abbey, it is only 

 7 or 8 feet deep, and is said by the workmen to rest on "clunch" 

 or chalk marl. This is certainly the case in a pit behind the 

 houses on the opposite side of the road to the Abbey Church, 

 whence large quantities of gravel and sand are now being 

 removed, the total depth being about 12 feet; underlying these 

 are one or two feet of marl resting immediately on the clunch 

 from which it has been mainly formed. Clunch comes to the 

 surface on the East, and coprolites are worked at a depth of 

 20 feet, thus a section through the above pits from N.W. to S.E. 

 would appear as in Fig. 6, for the use of which I am indebted to 

 H. M. Geological Survey. 



Fig. 6. Section through the Barnwell gravels. 

 Cam. Priory Road Pit 



Horizontal scale 9 in. to a mile ; vertical, 100 feet to an inch. 

 a — Gault. b = Chalk. c = Gravel. 



The gravel may be traced southward to the railway station, 

 where a long section was exposed in 1875, showing beds of 



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