CHAPTER IV. 



STRATIGRAPHY GENERAL SECTIONS. 



INTRODUCTION. 



The surface rocks of Lewis and Gilmer, with the excep- 

 tion of Quaternary sands and gravels along the streams, are 

 all of Paleozoic Age, only the Pennsylvanian Period being rep- 

 resented. The upper series, or Dunkard, of this period is gen- 

 erally conceded to be of Permo-Carboniferous age, represent- 

 ing a transitional stage between the Permian and Pennsyl- 

 vanian. Some evidence, however, is available, through numer- 

 ous oil and gas well borings scattered throughout the area, of 

 the thickness and character of the underground rocks, includ- 

 ing those of the Mississippian and upper Devonian beds. 



The following classification of the rocks available for 

 study shows their succession in convenient form, arranged in 

 descending order : 



Age. Period. Series. 



Quaternary. . . . \ Recent j Present Formation 



I Pleistocene [ River Terrace Deposits 



f Permo-Carboniferous ... Dunkard (550') 



| [ Mbnongahela (350-400') 



| J Conemaugh (500-650') 



| Pennsylvanian ] Allegheny (200-275') 



| [ Pottsville (400-800') 



Paleozoic \ 



| f Mauch Chunk (75-400') 



I Mississippian -{ Greenbrier Limestone (50-200') 



| [Pocono Sandstones (200-450') 



Devonian \ Catskill \ (500-650') 



I Chemung { 



The Quaternary rocks, in Lewis and Gilmer, are repre- 

 sented by clays, gravels and sand beds, present only along the 



