242 



lioned by Dr. C. T. Jackson ; they were found in digging a well, 

 and were recognized by Prof. W. as parts of a radius and ulna. 



Prof. Wyman said that he had come to the conclusion some 

 time since, that the Walrus should not be classified with the 

 Seals. Their dentition is quite different. That of the Seals 

 is the dentition of Carnivora, while the Walrus, besides its 

 tusks, is furnished with grinders having simple, blunt crowns. 

 Its stomach is elongated, and its food, so far as it is known, is 

 vegetable, consisting of the fuci of the shores on which it lives. 

 These facts, together with the thickness of the skin and the 

 form of the head, bring it much nearer to the Pacyhderms 

 than any other animals. It seems to hold the position with ref- 

 erence to the Pachyderms that Seals do with relation to the 

 the true Carnivora. 



Mr. Desor asked if Prof. Rogers had any theory to explain 

 the interruption of the drift mentioned by him at the pre- 

 ceding meeting as occurring w^est of the Alleghanies. 



Prof. Rogers replied, that he supposed the drift in coming 

 from the north had been turned aside by opposing obstacles, as 

 is indicated by a change in the direction of the drift scratches, 

 and by the greater thickness of the deposit where natural chan- 

 nels had been offered for it. In this way openings would be 

 left between diverging currents. 



Mr. Desor mentioned that on Lakes Superior and Michigan 

 the strise run from N. E. to S. W. One set runs due N. and 

 S. and is perhaps of more recent origin. 



Mr. Desor made some remarks on the relation of the 

 alluvium to the drift of the Mississippi. 



Mr. Lyell, he said, after a careful examination of the banks of 

 the Mississippi and Ohio, queried whether the bluffs were of the 

 same formation from Natchez to the Falls of St. Anthony. Mr. 

 Desor was of opinion that the Natchez bluff was analogous to, 

 and the continuation of, the low terraces or flat prairies at Cairo, 

 and on the eastern side of the Mississippi above St. Louis. His 

 opinion was based upon the fossil bones discovered in both local- 

 ities. The Natchez bluff he thought had been correctly ex- 

 plained by Mr. Lyell, who supposed that at the time of its 



