304 PROCEEDINGS OE THE ACADEMY OP 



the ridge on the west. From tliis point it is narrower and well 

 defined for a quarter of a mile to the next road parallel with the 

 Schuylkill. Here the stream seems to have denuded it for about 

 fiffc}'^ yards, and a stream from the east joins that on the west. 

 Beyond this it rises abruptly in a grove of cedars, and then con- 

 tinues, as a narrow, well-defined ridge, to its termination, which 

 is abrupt, about one and three-quarter miles from the Schuylkill. 

 In this part, as also in that between the two roads, it has almost 

 the regularity and appearance of an old railroad embankment. 



Hisingerite, from the Gap Mine, Lancaster County, Pa. Black 

 amorphous; lustre between resinous and vitreous; sti'eak, brown. 

 Fracture conchoidal, brittle H 2^-3 S. G. 2.11. 



Analysis omitting 1.13 per cent, gangue : — 



Water at 212 14.30 



" at redness 9.89 24.19 



Silica 35.40 



FeO 12.53 



Fe^Oj 27.46 



99.58 



In a cutting through decomposed mica shists, on the new line 

 of the Philadelphia, Wilmington, and Baltimore Railroad, about a 

 half mile southwest of Gray's Ferry, there is a white eflflores- 

 cence, alkaline to the taste. It consists chiefly of sulphate of 

 soda, an nnlooked-for mineral in such location. 



PHiLADELrniA, November 31, 1871. THEO. D. RAND. 



[February 13, 



