128-1 THE NATURAL 1IIST0I?T REVIEW. 



had sunk another well seven yards from the former, from an examina- 

 tion of Avhich Mr. Crosskey satisfied himself that the bed above 

 that containing the Shells is not the true Boulder-clay, but an 

 upper Drift, and that the Shells occurred in a hollow of the lower 

 clay, or true Till, filled up with a clay-deposit of an age interme- 

 diate between that of the other two. He therefore considers that 

 this can no longer be regarded as one of the fossils occurring in the 

 true Boulder-clay. 



February Sth, 1865. 



The following communications were read : — 1. *' On the Sources 

 of the Mammalian fossils of the Bed Crag, and on the Discovery 

 of a new Mammal in that Deposit allied to the Walrus." By E. 

 Bay Laiikester, Esq. Communicated by Professor T. H. Huxley, 

 E.B.S., F.O.S. 



The Mammalian fossils of the Bed Crag were stated to belong 

 to three groups : — (1) the teeth of Coryphodon, &c., derived from 

 Lower Eocene strata ; (2) the other terrestrial Mammalia ; and (3) 

 the Cetacenns. The Molluscan fauna of the Bed Crag was cited in 

 proof of its identity in age with the Upper or Yellow Crag of Ant- 

 werp, which contained none of the Bed Crag Mammals. The under- 

 lying Middle and Black Sands of Antwerp contain far larger per- 

 centages of extinct forms and very abundant Cetacean remains. The 

 deposits at Darmstadt and in the South of Erance, containing ter- 

 restrial Mammalia similar to those of the Bed Crag, are also anterior 

 to the Tellow Crag of Antwerp. The Bed Crag was thus shown 

 to include Mammalian fossils found nowhere else excepting in strata 

 of an earlier age. The probabilities therefore were, that these 

 various Mammalia were not indigenous to the Bed Crag, but were 

 derived from the breaking up of earlier strata ; and this supposition 

 was supported by lithological evidence, which the author gave in 

 detail, and discussed the chemical and the mineralogical questions in- 

 volved. Eurther evidence of the extraneous nature of the Mamma- 

 lian fossils was also adduced, in the fact that teeth of BhinGceros 

 and Mastodon occurred at the base of the Coralline Crag, and other 

 less conclusive facts were cited. The great abundance and perfect 

 condition of teeth of Car char odon and Ziphioid Cetaceans in the 

 Middle Crag of Antwerp, their absence in the Yellow Crag of that 

 locality, and their presence in a much rolled, indurated and frag- 

 mentary condition in the Bed Crag, often with portions of their 



