AMERICAN PERMIAN 429 



ill Prince Edward Island, Nova Scotia, and New Brunswick. 

 These beds are soft red shales and sandstones, which were laid 

 down in closed basins, not in the sea. In Pennsylvania and West 

 Virginia the Permian beds follow directly and without any break 

 upon the Upper Productive stage of the coal measures : they are 

 called the Upper Barren Measures, and consist of 1000 feet of 

 sandstones and shales with some limestone and a few seams of 

 coal. The character of these beds is entirely like that of the coal 

 measures, to which they were once referred, and their reference 

 to the Permian is due to the marked change which has come over 

 the vegetation. South of West Virginia no Permian beds have 

 been found in the Appalachian area, owing to the elevation of this 

 part of the region at the close of the Carboniferous, but the 

 Permian occurs in Illinois. 



As w r e proceed westward and southward through Missouri into 

 Nebraska, Kansas, and Texas, we find the Permian assuming much 

 greater importance, and becoming more and more prominently 

 developed in extent and thickness. A study of this region reveals 

 the fact that only a part — the lower — of the Permian is developed 

 in the Acadian and Appalachian areas. At the end of the Lower 

 Permian the entire series of the coal measures east of the Missis- 

 sippi River was elevated and the deposition of strata checked. 

 In the region beyond the Mississippi the Permian beds thicken 

 southward, attaining in southern Kansas a thickness of 2000 feet, 

 and in Texas of more than 5000 feet. The Ouachita Mountains 

 separate the Texas and Kansas areas, which were probably 

 covered by distinct bodies of water. 



The lowest beds of thesystem, in this western region, are shales 

 and limestones, which carry a transitional fauna of mingled Car- 

 boniferous and Permian types, followed by a characteristically 

 Permian assemblage. In southwestern Kansas the sea was then 

 excluded and salt lakes and lagoons took its place, in which sand- 

 stones and shales, with some dolomite, were accumulated, while 

 masses of gypsum and rock salt were precipitated from the dense 

 brines. These chemical deposits are now of much commercial 

 importance. 



