7S F 



KKPOl 



the presence of the plant bed in its middle? May not all 

 the beds of green and yellow shale owe their color to the 

 presence of vegetable or animal matter once buried in them \ 

 The green Chemung shales often abound with animal re- 

 mains. The red shales and sandstones of the Catskill may 

 have done the same, but the abundance of iron salts in so- 

 lution may have destroyed all but the great, solid fish-plates 

 of enamel. The casts and impressions of shells sometimes 

 obtained from the red locks indicate that life was not want- 

 ing in the seas nor its relics in the sediments of that age. The 

 green shales of the Chemung often contain casts showing 

 both the inner and outer marks of the shell on two surfaces. 

 This has probably been caused, as suggested tome by Prof. 

 Whitfield, by the removal of the shell by acidulated water. 



The upper beds of the Catskill. 



The upper part of the formation consists of harder sand- 

 stones, which make a bold ridge round the edge of the 

 outcrop. These beds may be well seen near Duncannon. 

 On the east side of the Susquehanna the N. C. railway has 

 exposed a fine section through them. They continue on 

 the west side forming Duncannon hill, a favorite resort for 

 the sake of the beautiful view that can be obtained from 

 its summit. A mile west of this point Sherman's creek 

 passes through this ridge in a very narrow and picturesque 

 gorge. 



Thence the sandstone continues under the name of Pine 

 hill, forming an outer rampart round the higher and steeper 

 Pocono mountain-wall encircling the cove. 



Near the middle of Carroll it returns eastward to the 

 Susquehanna under the name of The Ridge. It is here 

 less distinct than on the north side of the trough, the sand- 

 stone layers being apparently separated from the Pocono 

 bv less sofl material. 



No. X . Pocono sandstone. 



Two Y-shaped outcrops of this massive conglomeratic 

 sandstone project into Perry county. 



