200 PROCEEDINGS OF THE ACADEMY OF [1893. 



more layers containing fossil impressions of plant life. The layers 

 now becoming more uniform in their bedding planes, with one, and 

 sometimes both planes, smooth and parallel to each other, of a thick- 

 ness of 1 to 2h inches, the surfaces having a slight film of a rusty, 

 ferruginous color, sometimes bearing arborescent forms. These 

 layers were observed 6 to 10 inches wide, and would evidently get 

 more massive working into the side hill. The total thickness of the 

 pyrophyllite slates is about six feet to water level. This exposure 

 is on lands of R. J. C. Walker and Wm. Weightman of Philadelphia. 



