Geology and Geographj. 397 



the diluvial. The remaining genera of mammiferous animals can 

 be identified with those now existing, or with such as are found in 

 diluvial and lacustrine deposits. The author next notices the disco- 

 very of the mineralized remains of birds, chiefly bones of the ex- 

 tremities of natatorial tribes, a solitary instance of a similar disco- 

 very in America being the only one recorded. He was not pre- 

 pared to speak concerning the different kinds of fish, but he stated 

 their distribution — species of Squalus being found near Orford, 

 and what Agassiz conceives to be Platex, at Cromer. Among the 

 most remarkable is the Carcharias megalodon, the teeth of which 

 are found in Suffolk, equal in size to specimens from the tertiary 

 formations of Malta. He also alluded to the difference of the tes- 

 tacea in different parts of the Crag, from which he was inclined to 

 infer there were several eras in its formation. No traces of the ex- 

 istence of reptilia have yet been detected, which would rather sup- 

 port the opinion of Dr Beck and Deshayes, that the climate during 

 the Crag epoch was analogous to that of the Polar regions. — Pro- 

 fessor Sedgwick stated, that he had been long aware of the exist- 

 ence of remains of mammalia in the Norfolk Crag, although this 

 had been disputed by Mr Conybeare, in his work on the Geology 

 of England and Wales. He was rather inclined to consider the 

 Crag as all of one epoch ; and Mr Lyell had found existing species 

 as numerous in the lower as in the upper Crag. With regard to 

 Mr Charlesworth's idea of the extinction of the mastodon in Eng- 

 land before the formation of the diluvial beds, Professor Sedgwick 

 conceived that it was reasoning from a negative fact, and that until 

 more extensive search had been made, no such inference could be 

 fairly drawn. He also mentioned that remains of the beaver were 

 found in the alluvions of Cambridgeshire, and that it might have 

 existed in England a thousand years ago. He was confident that 

 no cause still in existence could have produced the diluvium on the 

 Crag ; its whole appearance suggested the idea of a great rush of 

 waters. — Mr Conybeare was perfectly willing to correct his opinion 

 respecting the existence of the remains of mammalia in the Crag. 

 He was of opinion that the tertiary strata of America had not 

 been sufficiently examined to justify the conclusion that it did 

 not contain remains of the mastodon. He started a question — 

 which of the species of mastodon fonnd in other countries did the 

 British one resemble ?— Mr Greenough mentioned, as a singular 

 peculiarity of the diluvium of Norfolk, its containing large masses 



