NATURAL SCIENCES OP PHILADELPHIA. 177 



July bth. 

 Mr. Lea, President, in the Chair. 

 Present thirty-seven members. 



Mr. Lea presented the following, which was referred to a committee : 

 Description of four new species of Exotic Unionidae. 



Mr. Lea read letters which he had received from Dr. Lewis of Mohawk, New 

 York, in which he mentions the astonishing number of dead shells of Anodonta 

 Lewisii, Lea, in the canal, also the immense number of dead specimens of Cycles, 

 as they lie in beds from three to eight inches deep. He says he had taken two 

 gallons of living specimens from an area of six by four feet. They do not bur- 

 row deeply in the mud, while the Unio goes down tivo feet. Mr. Lea compared 

 this mass with the great deposit of fresh water gasteropods at Milk Pond, N. J. 

 Dr. Lewis also collected specimens on the East Branch of the Unadilla, a small 

 stream fourteen miles south west of Mohawk, and got about 200 Anodonta Unadilla 

 DeKay= An. edentula, Say. Subsequently he visited Cedar Lake, a small body of 

 water in Herkimer County, the south shores of which were composed of a 

 greenish white marl, consisting of the remains of untold millions of shells. In 

 the middle branch of the Unadilla, Dr. Lewis says, " I stopped ju9t long enough 

 to find one living specimen to be sure it was there. Dead shells were not 

 rare, but I did not spend much time, only to learn the character of the stream, 

 so as to be able to verify your opinion that Anodonta Unadilla was only a local 

 variety of An. edentula, Say." 



Mr. Lea also mentioned that he had received specimens in alcohol of Unio 

 Kleinianus, Lea, from G. Hallenbeck Esq., of Columbus, Georgia, to which that 

 ardent naturalist called his attention, as possessing a branchial uterus in both 

 lobes of the bronchia on each side. This very remarkable feature in the functions 

 of the female of this species, constitutes the third which has been observed by 

 Mr. Lea, two he had formerly shown to the Academy, namely, that of Unio 

 multiplication, Lea, and rubiginosus, Lea. 



July 12th. 

 Vice-President Le Conte, in the Chair. 

 Present nineteen members. 



Prof. Holmes exhibited a collection of fossils from the post-pliocene 

 of South Carolina. He remarked : 



If we examine the collection of remains of vertebrated animals taken from 

 the post-pliocene or post-tertiary beds of South Carolina which I have the 

 pleasure of exhibiting this evening to the members of the Academy, we will be 

 surprised at the resemblance in many of the forms to corresponding parts of 

 some of our domestic animals, as the horse, dog, hog, bull, etc., and the ques- 

 tion may very naturally suggest itself are the living horses, dogs, hogs, rac- 

 coons, opossums, deer, elk, tapirs, beavers, etc., and the one hundred and fifty 

 species of mollusca now living on the coast, the descendants of the animals 

 whose remains we find fossil in these beds, or are these truly fossil remains, 

 and not accidental occupants of this deposit? 



My object is not to enter upon a discussion of these questions, but simply to 

 exhibit the collection, and state the facts connected with their discovery, and 

 the geological evidence of their being true fossils found in an extensive forma- 

 tion in the low country of South Carolina, included in a belt about ten miles 

 wide, and occupying depressions in the great marl bed of the Eocene period. 



Three distinct formations or beds are here supposed to belong to this post* 

 pliocene age. First the marine beds, composed of a gray sandy clay in which 

 are imbedded innumerable small shells, sometimes very comminuted, but of 

 species now common and living on the coast ; many of the large shells are 



1859.] 14 



