

Kansas, Oklahoma, New Mexico and Texas. 209 



For the present I shall not enter into any explanation of 

 these classifications or show the numerous discrepancies between 

 them. But I shall say only, that above what has been called 

 " Dinosaur sand " or the true Trinity, we have a certain num- 

 ber of beds, called Glen Rose, Paluxy, Caprina and Caprotina 

 limestone, Gryphsea rock and Walnut clays, Comanche Peak 

 chalk and Goodland limestone — some of which are placed 

 sometimes in the Trinity division, and at other times in the 

 Fredericksburg — which require a careful study before they are 

 placed either with the "Dinosaur sand " or with the Washita 

 division. With this reservation I shall proceed to present a 

 stratigraphic and paleontologic classification of the strata com- 

 prised between the undoubted Trias and the undoubted Upper 

 Cretaceous. 



A. Beginning with the base, we have first, the Trinity or 

 Bosque division. The first description of it was given by Mr. 

 Hill, in the second volume of the Arkansas Geological Survey, 

 1888. I repeat that I have shown with details, that the fauna 

 found in it is a Jurassic fauna, without a single form which 

 can be attributed to a Cretaceous species. In Pike County, 

 Arkansas, round Murfreesboro, the upper portion of the Trin- 

 ity division has been destroyed by denudation and erosion 

 after the upheaval and break at the end of the Jura period. 

 But it may turn out after more minute researches and observa- 

 tions, that the missing upper portion may be found in part, if 

 not in toto, somewhere between Murfreesboro, Pike Co., 

 Arkansas, and Tishomingo, Chickasaw Nation, in the Choctaw 

 Nation territory, at or near the small stream called Kiamishi or 

 Xiamashi, where Dr. Z. Pitcher found a small specimen of a 

 Gryphma, called by Dr. Morton Gryphcea Pitcheri. 



The geographical distribution of the Trinity division fol- 

 lows a curved line from Murfreesboro, Arkansas, to Tisho- 

 mingo, to Glen Rose, Somerville Co., to Bosque Co., and 

 Trevis Co. in Texas, crossing the Trinity River valley, from 

 which it received its first name from Mr. Hill. Two different 

 fades exist on that line. The first or Arkansas fades is com- 

 posed of various rocks, such as grayish yellow limestone and 

 argillaceous sand. The second or Bosque fades is less argil- 

 laceous, with more limestone, more especially in that portion 

 of the division which has been called " Glen Rose (alternating) 

 bed."* West of Travis Co. or Austin, a third fades makes 

 its appearance, formed only of sandstone yellow and white, 



* The superposition of some of the subdivisions referred to the Glen Eose is 

 doubtful, and some may belong- to a younger formation. The Paluxy sand has 

 also been classified by some as belonging to the Fredericksburg division, while 

 others place it with the Trinity saud, without intercalation of the Glen Rose. 



