88 



insertion is different. They are inserted directly into the 

 second branchial bone. Tiie little needle-like bones, which 

 in Leuciscus show such an ingenious contrivance, do not 

 exist in Catostomus. Mr. Ayres said he had found them 

 in all the species of Leuciscus which he had examined. 



Dr. C. T. Jackson, in reference to Mr. Desor's remarks 

 at the last meeting, stated, that on the coast of Maine, near 

 Newcastle, there exists an oyster bank, sixty feet thick, 

 similar to that on Nantucket, containing various species 

 of Mollusks, of which living specimens may be obtained in 

 the vicinity, but in deep water. Ignorant of this fact, and 

 knowing that they do not now exist on the shores of Maine, 

 Mr. Lyell had been led to the erroneous conclusion that 

 they now belong only to more northern latitudes. 



In reply to a question from Mr. Desor, as to his opinion 

 of the age of the American Continent in comparison with 

 that of the other continents. Dr. C. T. Jackson said, that it 

 was his belief that the American Continent was upheaved 

 the first, as the granite bears obvious marks of greater age. 

 Mr. Desor replied that he did not consider this evidence 

 conclusive as to the continent's having been upheaved above 

 the water level. 



Dr. Bacon presented, in the name of Mr. William Stimp- 

 son, specimens of dendritic oxyde of Manganese on slate, 

 from Charlestown, Mass., and Shark's teeth from the green 

 sand of New Jersey. He also presented minerals from 

 Mexico, consisting of silver ore, crystallized calcareous spar, 

 and calcareous sinter, from Rio del Munte and its vicinity ; 

 and opal from Guanaxuato, received in exchange, from 

 Lieut. J. McNab, U. S. A. He also announced that there 

 had recently been purchased by Mr. Alger, for the Society, 

 mineralogical specimens to the value of $'175; this being 

 the balance of a sum of ,^300, which Mr. A. had been 

 authorized to expend for this purpose, from the funds 

 raised by him in 1847 in aid of the Society. Dr. Bacon 



