182 



HISTORICAL GEOLOGY 



Strata, mostly of non-marine origin and containing much red 

 materials like those of Texas and Kansas, are also found in the 

 other western states where Permian rocks occur (see above, also 

 Fig. 110). 



True marine strata, some thousands of feet thick, are known in 

 Alaska, especially in the Copper River region. 



In Nova Scotia and New Brunswick the Permian also consists 

 mostly of red beds including conglomerates, sandstones, and shales. 



Fig. 110 



Late Permian or early Triassic "Red Beds" in Red Butte, eastern Wyoming. 

 The bright red strata are capped by a 30-foot layer of white gypsimi. (After 

 Darton, U. S. Geological Survey, Folio 127.) 



Thickness of the Permian. — In Pennsylvania and Ohio the 

 Dunkard series (Lower Permian only) shows a thickness of about 

 1000 feet. A thickness of 2000 feet for the whole system is re- 

 ported from Kansas; 5000 to 7000 feet in Texas; and 3800 feet 

 in Utah. In Nova Scotia and New Brunswick Permian strata 

 attain a maximum thickness of 8000 feet. 



Igneous Rocks. — Evidence of vulcanism during the Permian 

 period in North America is practically absent. 



