GEOLOGY OF THE REGION. G 5 . 41 



served. As this trough deepens southward the Mauch 

 Chunk shales come in, and then the PoUsville Conglom- 

 erate. Deepening now more rapidly as it approaches Car- 

 bondale, it begins to hold the lowest coal beds and finally 

 becomes the deep, complicated Scranton, Pittston and 

 Wilkesbarre coal basin. 



The descent of the Pocono Sandstone beds, in its eastern 

 wall, Moosic mountain, (in Clinton township, Wayne coun- 

 ty) is at the rate of 8° to 10°. 



West of the Lackawanna mountain the dip becomes 

 gentle and finally (in four or five miles from the center line 

 of the basin) horizontal. Then the rocks roll over and dip 

 gently northwestward towards the Tunkhannock. This roll 

 is on the line of one of the greatest of all the anticlinals of 

 Pennsylvania. Starting from the southeast corner of Sus- 

 quehanna county and running in a grand gentle curve 

 through Greenfield, Abingdon, and Newton townships 

 (Lackawanna county,) it crosses the Susquehanna river 7 

 miles above Pittston ; passes near Lehman and Harveyville 

 in Luzerne county ; Rohrsburg in Columbia county ; White- 

 hall in Montour county ; Watsonburg in Northumberland 

 county ; elevates the White Deer mountain in Union county ; 

 and finally brings up Lower Silurian rocks in Sugar Valley 

 (Clinton county,) in Middle Pennsylvania. 



It is the grand geological divide between the Third An- 

 thracite Coal Field on the south and the Alleghany moun- 

 tain coal fields to the north. 



The south and southeast dips of this anticlinal, in its 

 western and middle course, become east dips at its eastern 

 end, where it curves up through Clifford, Herrick and 

 Ararat townships in Susquehanna county ; and these east 

 dips although gentle can be seen along the upper course of 

 the Lackawanna creek. 



As the escarpment of the North or Allegheny mountain 

 represents the north and northwest dips of this anticlinal 

 in Wyoming county, so when these become west dips, they 

 are represented in the outlying Pocono Sandstone peaks of 

 the Elk mountains in Gibson, Herrick and Clifford town- 

 ships in Susquehanna county. 



