CORRELATION OF CARBONIFEROUS ROCKS 355 



that the gvpsum beds of the Cave Creek formation, the top of 

 which is about 250 feet below the summit of the Kansas Red- 

 beds, apparently connect them "jby a bond of stratigraphic con- 

 tinuity with the demonstrated Permian of Texas." 1 



Fossils have recently been found about 100 feet above the 

 base of the Cimarron group in the northern part of Oklahoma. 

 The most abundant specimens are species of a Phyllopod Crus- 

 tacean which unfortunately were poorly preserved and, there- 

 fore, identified with some doubt by Professor T. Rupert Jones 

 as Estlieria minuta Alberti sp. 2 This species is characteristic of 

 the Triassic in England, France, and Germany, apparently 

 occurring most abundantly in the Keuper of the Upper Triassic. 



Associated with the Crustacean fossils was the greater part 

 of the skeleton of an Amphibian which has been identified by 

 Professor Williston " as Eryops megacephalus Cope, a form 

 described from the ' Permian ' of Texas." Professor Williston, 

 in discussing the importance of this discovery in reference to the 

 age of the Red-beds, says: "This identification settles once for 

 all the horizon whence it came as Permian, if the Texas beds be 

 really of that age. There are several hundred feet of deposits 

 in Kansas above this horizon that still possibly may be consid- 

 ered as Triassic, but there is no reason for so doing. Estlieria 

 minuta is a Triassic species, but, even if correctly determined, 

 its value is slight in comparison with that of the vertebrate in 

 the correlation of the beds. It must be remembered, however, 

 that Eryops is by no means necessarily characteristic of the Per- 

 mian." 3 



Professor Williston has written me as follows reo-ardino" 

 Cope's correlation of the Texas deposits with the Permian : " In 

 his first work upon the Texas beds Cope determined them as 

 Triassic, and he seems never wholly to have overcome the idea 



"Colorado College Studies, Vol. VI, p. 5 ; see also pp. 2, 3, 30, 48. The correla- 

 tion of the Red-beds from this stratigraphic evidence was discussed by the writer in 

 the Univ. Geol. Surv. Kans., Vol. II, pp. 89-92. 



2 Geol. Mag., Dec. IV, 1898, Vol. V, p. 292. 



3 Science, N. S., Vol. IX, Feb. 10, 1899, p. 221. 



