NATURAL SCIENCES OF PHILADELPHIA. + 107 



S. Lewis, Mr. Tryon Reakirt, Mr. Edward K. Tryon, Jr., Rev. George 

 D. Boardman, Lemuel J. Deal, M. D. r 11. L. Webber, M. D., U. S.N., 

 Mr. Samuel R. Shipley, Mr. William Sellers, and Mr. Joseph Walton. 

 The following were elected Correspondents : Prof. Alfred DuBois, 

 Colorado, Mr. Jacob Staufier, Lancaster, Pa., and Br. J. H. Baxter, 

 U. S. A. 



May 1st. 



Mr. Cassin, Vice-President, in the Chair. 



Twenty-five members present. 



The following was presented for publication : 



" Notes on some members of the Feldspar Family." By Isaac Lea. 



May Sth. 

 The President, Dr. Isaac Hays, in the Chair. 

 Twenty-four members present. 



Dr. Ruschenberger stated, in relation to the fossil fish-scales presented this 

 evening, that Col. James Greer, of Dayton, Ohio, had found them, March 19, 

 1866, with the bones of the head, ribs, vertebrae, &c, of the fish, about two 

 miles north of Vicksburg, Miss., on the river side of Fort Hill, about two hun- 

 dred feet above high-water mark, in the escarpment of a narrow road-way, 

 imbedded in the solid earth in a direction from north-west to south east, four 

 feet beneath the top of the bank or surface. Dr. Leidy supposes these scales 

 to be identical with those of an existing species of the Mississippi. 



May 15/A. 

 Mr. Vaux, Vice-President, in the Chair. 



Thirty-one members present. 



The following were presented for publication : 



" On the Structure and Distribution of the Genera of the Arciferous 

 Anura," and " Fourth Contribution to the Herpetology of Tropical 

 America." By E. D. Cope. 



" Description of five new species of Unio," and " Description of two 

 new species of Lithasia." By Isaac Lea. 



" Observations on the Cranial Forms of the North American Indians." 

 By J. Aitken Meigs, M. D. 



Mr. Benjamin Smith Lyman observed : I have the honor of presenting to the 

 Academy a fine Slickenside in the carboniferous conglomerate, found at Ply- 

 mouth, Luzerne County, Pennsylvania. The Slickenside covers a surface of 

 irregular shape, eight inches and a balf long in the longest part and sixteen 

 inches wide ; and is very smoothly and straightly grooved, evidently by the 

 rubbing of one portion of the rock upon the other, ft bus struck me as inte- 

 resting chiefly on account of its giving a perfectly satisfactory explanation of 

 what have been sometimes taken for fossil calamites that had impressed them- 

 selves upon the quartz pebbles of the conglomerate so as to flatten and groove 

 them. Such impressions were mentioned by Professor Jehu Brainerd of Cleve- 



1866.] 



