1856.] 259 



November ^th, 1856. 

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



Letters were read 



From the Imperial Academy of Science and Belles Lettres of Lyons, 

 dated July 14th, 1856, transmitting itsMemoires. 



From the Linnean Society of Lyons, dated July 9th, 1856, of the 

 same tenor. 



From the Imperial Society of Agriculture, Natural History, and the 

 Useful Arts, of Lyons, dated July 8th, 1866, of the same tenor. 



A paper was read, entitled " Description of a new Species of Tanager 

 of the genus Saltator, by Philip Lutley Sclater." Referred to a com- 

 mittee consisting of Dr. T. B. Wilson, Mr. Cassin, and Dr. Hallowell. 



Mr. Lea presented a paper entitled " Descriptions of Eleven new 

 species of Unioues from Georgia, by Isaac Lea.'' Referred to a com- 

 mittee, consisting of Dr. T. B. Wilson, Mr. Binney, and Dr. Leidy. 



Mr. Lea read portions of a letter from Dr. J. Lewis, dated Mohawk, 

 N. Y., October 28th, 1856, giving a list of living mollusca in " Little 

 Lakes," Otsego, County, ^N. Y. Referred to the Committee on Pro- 

 ceedings. 



" The geological character of the basin in which the upper or northern Lake 

 lies, is sufficiently explained by the out-cropping rocks of " Coriferous lime- 

 stone " that appear near its eastern and western shores. The bottom of the 

 lake was formerly, no doubt, either a stratum of the " Coriferous " or the 

 " Onondaga Limestone " of the New York Geological surveys. 



The lake is fed by a few small streams that drain a considerable extent of 

 territory of the same geological character, and it is fair to presume that a con- 

 siderable quantity of lime enters the lake in solution, where, by the influences 

 of light, heat, evaporation, and animal and vegetable life, most of the lime is 

 deposited in the form of a greenish grey mud, in which are immense numbers 

 of shells, which are perhaps the accumulation of ages, and form in the lake and 

 the surrounding marshes beds of marl, in many places over 20 feet deep. In 

 such a locality the mollusca might be expected to exhibit some unusual or 

 singular features, and such indeed is the case. 



The species that have fallen under my observation have been sought only in 

 the upper lake. The lower lake (which does not exhibit the marl of the upper 

 to any remarkable extent) is so variable in its depth, from being raised or 

 lowered to meet the requirements of a mill on its outlet, that a favorable oppor- 

 tunity for examining it has not occurred at such times as could be made availa- 

 ble. The species do not differ, so far as known, from those of the upper lake. 



Unio radiatus (var ?) Lam. 



Anodonta ? between fragilis and fluviatilis. 



Cyclas similis, Say, In shallow water. 



Cydas rhomboidea, Say. Borders of marshes. 



Cyclas crocea, Say. Borders of marshes. 



Pisidium variahile. Prime. 



Pisidtum compressum. Prime. 



Pisidium ventricosum. Prime, (obtusale ? Pff.) 



Lymncea gracilis, Jay. Dead shells only seen in fragments. 



Lymnoea columella, Say. On aquatic plants. 



Lymncea appressa, Say. One dead shell seen only. 



PROCEED. ACAD. NAT. SCI. OF PHILADELPHIA, VOL. VIII. NO. VI. 20 



