X. Notice on the Occurrence of Land and Freshwater Shells ivith Bones of' some 

 extinct Animals in the Gravel near Cambridge. By P. B. Brodie, F.G.S , of 



Emmannel College. 



[Read, April 30, 1838 ] 



The discovery of recent shells associated with bones of some extinct mammalia, and other animals, 

 is a subject of considerable interest, especially as the same fact has also been noticed in several 

 other distant localities. The shells in question were found in a gravel pit at Barnwell, ad- 

 joining the river, in a bed of fine sandy gravel, about fourteen feet from the suiface, the whole bed 

 consisting of alternating layers of fine white sand and pebbly gravel, resting upon a thin bed of 

 brown clay ; altogether amounting to a thickness of about twenty feet. The stratum in which 

 most of the shells occur is composed of a thin bed of shelly gravel, abounding in many perfect 

 specimens, and comminuted fragments of the same fossils. To this succeeds an equally thin 

 bed of fine white loam, containing shells far more perfect but less numerous. This gravel, though of 

 course derivative, appears to differ from the coarser beds of the same formation ; for while the 

 latter chiefly consist of rolled fragments of older rocks, the former, on the other hand, contains 

 but a small proportion of such materials, and appears to be more immediately derived from a 

 finer sediment formed by local inundations. Indeed, many of the terrestrial and aquatic shells 

 are of so fragile and delicate a texture, that they must have been inevitably injured had they 

 been swept away by any violent aqueous action. In most of the specimens, the mouths of the 

 Univalves, and the hinges of the Bivalves, are in excellent preservation, whilst the associated 

 bones exemplify the same fact. The shells are also very abundant, and generally of small size ; 

 all the genera, and most of the species being identical with those now living, though one or 

 two species do not appear to be so. Among the terrestrial specimens the following genera and 

 species may be enumerated. 



Helix hortensis. 

 carthusiana. 



■■ \ ICi 



Bulimus clavulus. 

 Claiisilia. 



f Pupa umbilieata. 



sex-dentata. 



The aquatic shells afford examples of the following genera : 

 Cyclas, a new species. 



Succinea amphibia. ' 



oblonga. \ 



species undetermined. ) 



Paludina, species undetermined, f 

 Operculfe of | 



Valvata obtusa. 

 spii'orbis. 



Planorbis niarginatus. 

 and some others. 



[ LjTiincea aujicularis. 



1 glutionosa. 



species undetennincd. 



Tcstacellus. 



The above undetermined species may not, perhaps, have any living representative. The Rev. 

 Leonard Jenyns has decided the Cyclas to be a new species. Seed-vessels of Chara or Gyrogonite, 

 and wood partly charred accompany them. 



The bones discovered in the shelly gravel consist of the following specimens. A large tibia 

 and a small molar tooth of an elephant. Tibia of the gigantic ox. Lower portion of the horn 

 of a stag. Tibia of a deer, with teeth and vertebra; of the same animal. From the brown clay 

 forming the basis of the gravel, and overlying the chalk marl, was obtained the pelvis of a 

 small elephant ; but no shells occur in this bed. Some of the other localities, in which I have 

 also observed the same facts, are in the neighbourhood of Maidstone in Kent, and Salisbury in 



