DEEPENING OF THE CKETACEOUS SEAS. 515 



That this gradual deepening of the Comanche Peak waters continued 

 southwestward into Mexico and perhaps South America, there is every 

 evidence, although in northern Mexico and the trans-Pecos region there 

 has been such extensive disturbance and extreme metamorphism that the 

 identity of the paleontologic and stratigraphic subdivisions is lost. 



THE WASHITA OR INDIAN TERRITORY DIVISION. 



General Aspect. — This division has its prevalent and characteristic de- 

 velopment in southern Choctaw and Chickasaw nations of Indian territory, 

 and in northern Texas, in Grayson, Cook and Tarrant counties, where it is 

 the predominant formation. It extends southward to the Rio Grande at Del 

 Rio, but becomes greatly changed in lithologic character, assuming a more 

 calcareous aspect and decreasing in thickness. 



The Ccqwuia limestone is apparently the culmination of the great subsi- 

 dence of the Comanche series, for above that terrane the strata begin to dis- 

 play more and more a littoral aspect, and new faunas appear. To this 

 division I give the name of Washita, after old Fort Washita, in the Chicka- 

 saw nation, where the beds were first noted and described as Neocomian by 

 Marcou. In order to appreciate this division in the region of its greatest 

 development, we must transfer our attention from central Texas to southern 

 Indian territory and the Red river basin. 



The Kiamitia Clays or Schloenhachia Beds. — In southern Indian territory 

 and northern Texas the chalky Goodland (Comanche Peak) limestones, 

 w^hich I consider the northern attenuation of the Comanche Peak beds, are 

 succeeded by another large development of marly clays, often stiff and black 

 before oxidation, and accompanied by thousands of individuals of the 

 variety of Grypha^a pitcher I so accurately figured by Marcou and White (G. 

 foriiiculata of White), as I have determined by visiting the original locali- 

 ties of Morton, the plains of the Kiamitia. Another conspicuous and char- 

 acteristic fossil of these beds is the Schloenhachia acufecarinatus, Shumard 

 {= Ammonites peeler nalis, von Buch). Alternating with the clays there are 

 firm, hard, thin dimension layers, composed almost entirely of these shells 

 imbedded in a matrix of yellow lime. The buildings at old Fort Washita 

 are constructed of this stone. These clays were first seen by me at Cerro 

 Gordo, Arkansas, where at first I confused them with the Arietina clays ; 

 and they are developed westward through Indian territory continually to 

 the great southward deflection of strike west of Marietta (Chickasaw nation), 

 whence they continue southward into Texas. 



Among the typical localities in Indian territory where the Kiamitia clays 

 are unmistakably seen and constitute large areas of land are the following : 

 At and around the town of Goodland, on the St. Louis and San Francisco 

 railway north of Paris ; thence westward to Fort Washita ; at the Folsom 



