NATURAL SCIENCES OF PHILADELPHIA. 71 



" Description of two uew Fossil Shells from the Upper Amazon." 

 By T. A. Conrad. 



Anali/sis of Graphite from Wythe County, Virginia. By E. 

 Goldsmith, Of all the varieties of Graphite that have come 

 under my notice, I have never seen any resembling that which was 

 given to me recently by Mr. John C. Trautwine, C. E. It is com- 

 pact massive ; the touch is smooth. If cut with a knife or scratched 

 with the finger nail, it shows a bright dark metallic lustre. The 

 fracture is rough, uneven, dull. The color is dark blue, so that 

 the mineral greatl}^ resembles the massive earthy vivianite of New 

 Jersey. The powder has the same color. 



Talc makes an impression on it, hence its softness is less than 

 one. Lines drawn with it on paper are of a dark gray hue, similar 

 to common soft lead pencil marks. Specific gravity = 2.1068. 

 The blowpipe reactions, as well as my qualitative analysis, showed 

 that beside the carbon a large proportion of silica, alumina, and 

 iron oxides, also a trace of manganese, were present. The mineral 

 contains a considerable amount of gas, the quantity and reactions 

 of which I had not the means to ascertain. 



The quantitative determinations of the amount of moisture and 

 gases, the carbon, and ashes were found in the same manner as is 

 usually adopted in the analysis of anthracite. 



These were the results : 



Carbon 29.12. 



Ashes 60.61. 



Gases and moisture . . . 10.27. 



Showing that the mineral may be regarded as a very impure gra- 

 phite. 



May 12. 



The President, Dr. Ruschenberger, in the chair. 

 Twenty-seven members present. 



Notice of some New Fresh-water Rhizopoda. Prof. Leidy re- 

 marked that besides the ordinary species of Amoeba, which he had 

 observed in the vicinity of Philadelphia, he had discovered what 

 he suspected to be a new generic form. It has all the essential 

 characters of Amoeba, but in addition is provided with tufts of 

 tail-like appendages or rays, from which he proposed to name the 

 genus Ouramceba. 



The rays project from what maj' be regarded as the back part 

 of the body as the animal always moves or progresses in advance 

 of the position of those appendages. The rays are quite different 

 from pseudopods, or the delicate rays of the Actiuophryens. 



