630 A. W. GRABAU TYPES OF SEDIMENTARY OVERLAP 



That the Pocono is non-marine is shown by the absence of fossils, ex- 

 cept as noted below. The fact is further indicated by the relationships 

 of the strata, which conform to the non-marine type of overlap. The 

 source of the material of this formation was in the Appalachian old- 

 lands on the southeast, as is shown by the decreasing coarseness toward 

 the northwest, and by the fact that no land capable of furnishing the 

 material of this rock existed in Ohio, western New York, or Canada, 

 which were extensively covered, at the time of the formation of the 

 Pocono, by marine Devonic strata, many of them limestones. The char- 

 acters of this formation will be best shown by two sections from the 

 eastern area. 



1. Section of the Pocono in the Northern Anthracite Fields, in Wayne County, 



Pennsylvania, aoout 10 Miles South of the New York Line* 



Feet 



8. Sandstone 40 



7. Shale and sandstone 200 



6. Massive sandstone 125 



5. Shale and current bedded sandstone 265 



4. Griswold Gap conglomerate 35 



3. Sandstone and shale, imperfectly exposed 150 



2. Sandstone and sandy shale 200 



1. Mount Pleasant conglomerate 25 



Total 1,040 



0. Catskill. 



Beds 1 to 3 are regarded by White as transitions from the Catskill. 



II. Section at Pottsville.-f 



Feet 



6. Sandstone, more or less conglomeratic 521 



5. Slate 22 



4. Sandstone, with much conglomerate 726 



3. Sandstone with little conglomerate 240 



2. Sandstone, variegated 409 



1. Red, gray, olive, and yellow sandstone, with some shales and con- 



glomerates, transitional from Catskill 525 



Total 2,443 



0. Catskill. 



On the Susquehanna the formation is 2,000 feet thick. It becomes 

 coarser toward the southeast, the pebbles in Maryland being sometimes 



* Stevenson : Lower Carboniferous of the Appalachian basin. Bull. Geol. Soc. Am., 

 vol. 14, 1903, p. 18. (Slightly altered.) 



I. C. White : Second Geol. Survey of Pennsylvania, G 5, 1881, p. 56. 

 t Stevenson : Loc. cit. 



