69 



on the coast of the Polar sea near the Mackenzie in considerable 

 quantity. This formation contains layers of a variety of pipe-clay which 

 is eaten by the natives, and is said to sustaih life for a considerable 

 time. The deposit at the mouth of Bear Lake River includes some 

 beds of impure porcelain earth. The author found occasionally much 

 difficulty in distinguishing the sandstones and shales of this deposit, 

 from those of the formation mentioned above in Section 5. 



8. Among the indications of other strata more recent than the 

 magnesian limestone, was a loose fragment of soft limestone found 

 at the mouth of Babbage River, on the coast west of the Mackenzie, 

 containing the species of Cyclas (C. medius) which occurs extensively 

 in the weald-clay of England. 



This memoir, which will be published in full in the Appendix to 

 Captain Franklin's Narrative of the expedition, is illustrated by maps 

 and drawings, and accompanied by a catalogue in detail, of the 

 specimens referred to, which have been presented to the Geological 

 Society. 



April 18. — William Hutton, Esq. of Newcastle-upon-Tyne, Beriah 

 Botfield, Esq. of Christchurch Oxford, and William Parker Hamond, 

 Esq. of St. John's College Cambridge, were elected Fellows of this 

 Society. 



A Paper was read, " On the fossil remains of two new species of 

 Mastodon, and of other vertebrated animals, found on the left bank of 

 the Irawadi ; by William Clift, Esq. F.G.S. F.R.S., conservator of the 

 Museum of the Royal College of Surgeons." 



The author having been requested to describe the fossil remains 

 wtich the zeal and liberality of Mr. Crawfurd have transferred from 

 the deserts of the Irawadi to the Museum of the Geological Society, 

 coifines himself strictly to zoological and anatomical details ; and fol- 

 loving the system of Cuvier, commences with the 



Pachydermata proboscidifera. — The only genus of this order indi- 

 «ated by the remains is the Mastodon ; and of this there are two spe- 

 ues, Mastodon latidens and Mastodon elephantoides, not only com- 

 nanding attention from their novelty, but from the beautiful gradation 

 vhich they exhibit between the mastodons already described and the 

 eephant. On comparing the teeth of Mastodon latidens with those 

 d the mastodon of the Ohio (M. giganteum) the denticules are found 

 ti be more numerous, and less distant, and the interstices less deep 

 tlan in those of the latter. The teeth, in short, begin to assume the 

 apearance of those of the elephant. On advancing to Mastodon 

 eiphantoides, these features of similarity are more strongly deve- 

 loed : the many-pointed denticules are still more numerous and 

 rare compressed ; and the structure, were it not for the absence of 

 ensta petrosa, becomes almost that of the tooth of the elephant. 

 Ir both, though the teeth are formed upon the principle by which 

 th tooth of the mastodon is distinguished from that of the elephant, 

 th crown of the tooth wears away more like that of the elephant than 

 tV.t of the other mastodons. 



