THE PERMIAN PERIOD. 621 



development, though far less wide-spread than the Pennsylvanian. 

 The Permian strata are best known in Texas, Kansas, and Nebraska, 

 and though the sea was not entirely excluded from this region, it 

 appears, where present, to have been shallow. Locally and tempo- 

 rarily, inland seas were cut off from the ocean. Early in the period 

 the Texan area of sedimentation seems to have been separated from 

 the Kansan by the beginnings of the Ouachita mountains, the uplift 

 of which has been mentioned. 



In Kansas l and Nebraska 2 the older Permian beds are marine, 

 and though the connection has not been traced, the Permian of these 

 states is probably continued northwestward to Wyoming 3 and South 

 Dakota, 4 for in the Laramie mountains of the former state, and in 

 the Black Hills of the latter, marine Permian beds, with fossils very 

 similar to those of Kansas, are found. The marine Permian of Kansas 

 is overlain by beds containing gypsum and salt, and possessing other 

 features which show that the open sea of the region was succeeded 

 by dissevered remnants, or by salt lakes whose supply of fresh water 

 was exceeded by surface evaporation. Connected with these saline 

 and gypsiferous deposits, and overlying them, are the "'Red Beds," 

 sometimes referred to the succeeding Trias; but they appear to be 

 late Permian, in the main at least. This conclusion seems applicable 

 to a large part of the Red Beds east of the mountains, though some 

 are probably Triassic. Some of the Red Beds in western Texas and 

 New Mexico are perhaps later than Permian, and some in Indian Ter- 

 ritory and Kansas are possibly the equivalent of portions of the Penn- 

 sylvanian system. 



The gypsum beds of Iowa may be of Permian age, though there 

 is nothing in their relations to make this certain. 5 



1 For an account of the Permian of Kansas see Prosser, Geol. Surv. of Kansas, 

 Vol. II, 1897, pp. 55-97. This article also contains references to the litera- 

 ture concerning the Permian of the western interior. See also papers by the same 

 author on " The Permian and Upper Carboniferous of Southern Kansas," Kans. 

 Univ. Quar., Vol. IV, 1897, p. 149, and on " The Classification of the Upper Paleozoic 

 Rocks of Central Kansas," Jour. Geol., Vol. Ill, pp. 682-705, and Vol. X, pp. 703-37; 

 Cragin, Permian System of Kansas, Colo. College Studies, Vol. VI, pp. 1-48; Gould, 

 Jour. Geol., Vol. IX, pp. 337-40; and Beede, Am. Geol. Soc, XXVIII, p. 47; and 

 Prosser and Beede, Cottonwood Falls, Kan. folio, U. S. Geol. Surv. 



2 Knight, Jour. Geol, Vol. VII, pp. 357-74, and Barbour, Nebraska Geol. Surv., 

 Vol. I, p. 129. 



3 Knight, Bull. 45, Wyo. Experiment Station, and Jour. Geol., Vol. X, pp. 413-22 

 * Darton, 19th Ann. Rept.,U.S. Geol. Surv.,Pt. IV. 



6 Wilder, Iowa Geol. Surv.. Vol. XII, p. 111. 



