1893.] NATURAL SCIENCES OF PHILADELPHIA. 199 



are black on the line of the fossil markings; and, as this exposure 

 is all above any heavy body of water, it forms a good point of obser- 

 vation for a full order of superposition, though narrowness between 

 the banks of the run, with green timber growing thereon, is a bar 

 to any extensive investigations as to quantity or extent of the same. 

 The measures are all somewhat irregular on their bedding planes, 

 but give a nearly flat surface on one plane. The entire deposit is 

 ten to twelve feet in thickness, of which the pyrophyllite slates pi-oper 

 occupy about five feet of the upper portion of the measures, and is 

 the only full section that has been seen. 



The fifth exposure occurs on Bear Run, a tributary of Little Pine 

 Creek, abotit two and a half miles from the mouth of the Run, on 

 the south bank above the forks. It adjoins the edge of the 

 Run, and is partly below water-level, a great hindrance to the 

 full and proper study of the section, which presents itself under 

 more inviting surroundings than any of the preceding exposures 

 in the extent and quality of the outcrop, as well as its very 

 interesting occurrence. It occurs at the foot of the side hill, about 

 1,400 feet above tide, in a cliff ten to twelve feet high, and fifteen to 

 twenty yards in length. The overlying rocks are red and gray shales 

 and sandstones, of Formation Kb. IX, Catskill group, and the roof 

 rock is a calcareous ferruginous sandrock (with small nodules of red 

 oxide of iron disseminated through it) in part coming in as a wedge, 

 while another portion of the measures further west — a brownish, 

 rotten sandrock — is the cover, immediately under which occurs a 

 thin, shelly, fissile, red slate, six to eight inches thick. This is 

 followed by two feet of very soft, gray, fissile slates, T V to |-inch in 

 thickness, increasing to i-inch with much exfoliation. These may 

 be only the result of weathering at the surface, as it was observed 

 in going in on the measures a short distance, they became somewhat 

 thicker and more solid. The slates on the outcrop were quite soft 

 and aluminous (hardening on exposure). In a few of the layers 

 were impressions of algae (?) ; on others, numerous rough accretions 

 on the surface, simulating small fossil shells. Proceeding downward, 

 the slates assumed a more distinct layerlike appearance, and became 

 thicker, being T-inch to lb inches — one surface was generally quite 

 smooth and flat, while the other would be somewhat irregular. Upon 

 getting into these thicker layers, the removal of them opened up 

 many odd and interesting forms resembling aboriginal stone imple- 

 ments. Below these the slates became thicker to water level, with 



