117 



Messrs. Foster's and Desor's theories would require. On the 

 other hand, the shells discovered by Mr. Lyell near Montreal 

 were much broken and worn, and had evidently, he thought, 

 been swept up from below and lodged in angles and depressions. 

 Prof. Rogers also stated that in studying the geology of Pennsyl- 

 vania during a period of ten years, he had found no marine 

 fossils in the drift. 



Mr. Desor remarked that Prof. Rogers's theory would not 

 account for the regularly stratified ridges of six hundred, seven 

 hundred, and nine hundred feet in height found in Ohio, which 

 were probably at various periods the shores of vast collections of 

 water. 



Dr. Bacon announced the donation from Prof. J. W. 

 Webster of five specimens of Idocrase, from Sanford, Me., 

 the new locality of this mineral discovered by him last sum- 

 mer. From Francis Alger, Esq., two specimens of oxide 

 of Tin from Cornwall, two of the rare mineral Murio- 

 phosphate of Lead from Keswick, Cumberland, and one of 

 Phosphate of Lead from the same locality. 



Mr. Joseph W. Balch and Dr. Geo. A. Bethune were 

 elected members of the Society. 



February 21, 1849. 

 The President in the Chair. 



Present, fourteen members. 



Dr. Gould stated a fact bearing upon the question dis- 

 cussed at the last meeting, as to the nature of the Ohio 

 clay formation containing the mastodon bones. Up to the 

 time of Mr. Lyell's visit to that State, geologists had sup- 

 posed and asserted that no shells existed in that deposit. 

 Mr. L. however, succeeded in finding at Big Bone Lick six 



