1 56 The American Geologist. September, iocs 
nant red colored formation composed of sandstones, clays and 
shales, gypsum and salt-bearing, unfossiliferous, comparable to the 
Russian Tartarian stage.* 
The Tartarian is the upper stage of the Russian Perm- 
ian and some of the Russian geologists have considered it 
as of Triassic age. Under the Carboniferous system Dr. 
Kayser said : 
We find in the states of Kansas, Nebraska, Utah, Arizona, 
Nevada, etc. as in central Russia, an almost exclusively marine, 
chalky development of the Upper Carboniferous, which gradually 
passes above into the marine Permian.t 
Since the above was written Dr. George H. Girty has 
published a paper entitled "The relations of some Carboni- 
ferous faunas"* in which he provisionally correlates the 
upper Paleozoic formations of Trans-Pecos, Texas with 
those of Russia and Kansas. In order to understand the 
nomenclature applied to .the geological divisions of this 
region it is necessary to state that Dr. Girty in 1902 pro- 
posed the name Guadalupian for apparently all the Pale- 
ozoic deposits succeeding the Pennsylvanian of that re- 
gion which he stated : 
"Shall be employed in a force similar to Mississippian and 
Pennsylvanian."* 
The title of his paper "The Upper Permian in western 
Texas" indicated the age of the series. This region was 
studied later by Mr. George B. Richardson who has named 
the formations and referred the Hueco to the Pennsylvanian 
series, the Delaware Mountain formation and Capitan lime- 
stone to the Permian series to which also the Castile gypsum 
and Rustler formations are doubtfully referred.* 
It is to be remembered in passing that the term "Dela- 
ware Mountain formation" is so similar to the Delaware 
limestone of Orton, a name applied in 1878 to a Devonian 
formation of Ohio,t that it is not a sufficiently distinctive 
designation for the Texas formation. In fact it has already 
"been referred to as the Delaware formation which will cer- 
tainly lead to confusion. 
Dr. Girty discusses to some extent Dr. Tschernyschew's 
* Iiehrbuch d. geol. Formationskunde, 2d ed., 1902, p. 264. 
t Ibid., pp. 205, 206. O 
+ Proc. Washington Acad. Sciences, vol. vii, June 20, 1905, pp. 1-26. 
* Am. Jour. Sci., 4th ser., vol. xiv, p. 368. 
* Univ. Texas Min. Surv., Bull. 9, November, 1904, pp. 32-45. 
f Rept. Geol. Surv. Ohio, vol. iii, p. 606. 
