222 Bulletin of Laboratories of Denison University. [Voi. xi. 
there is a slight difference in dip between the older and later 
strata in the same series, while the Permian is conformable with 
the Coal Measures below, and unconformable with the Triassic 
above. The Permian in Texas attains a thickness of at least 
five thousand feet. 
Permian was first reported in Texas by Jules Marcou in 
^ 853 - 54 -^ Dr. William De Ryee (1868), Prof Jacob Boll (1 880), 
Prof C. G. Broadhead, Prof E. D. Cope, and Dr. C. A. 
White referred the Texas beds to the Permian, while Prof 
Edward Hitchcock in a report based on the notes of Capt. 
Marcy’s exploration of the Red River in 1852 referred them to 
the Cretaceous.^ 
Prof Cummins divides the Permian of Texas into three 
divisions, under the names of Wichita Beds, Clear Fork Beds, 
and Double Mountain Beds. The Wichita Beds (1800 feet) are 
composed of sandstones, clay beds and a peculiar conglomerate, 
while the portion formerly referred to the Coal Measures under 
the name of Albany Beds, consists largely of limestones and 
clays. The Clear Fork Beds (1975 feet) are composed of lime- 
stones, clay and shale beds, and sandstones, and the Double 
Mountain ^Beds (2075 feet) of sandstones, limestones, sandy 
shales, red and bluish clays, and thick beds of gypsum. 
The Shinarump Conglomerate of Major Powell, which Mr. 
C. D. Walcott places as the divisional line between the Permian 
and Triassic, seems to be a very constant horizon, and is re- 
ported by Dutton from the Grand Canon district. Prof Cum- 
mins adopts this horizon as the line between the Permian and 
Triassic of north-western Texas. 
Fossils have been found in all three divisions of the Red 
Beds of Texas, Triassic types occurring in the lower beds along 
with Coal Measure and Permian forms, while characteristic Per- 
mian forms have been found within 300 feet of the top of the 
Double Mountain Beds. No systematic attempt has been made 
to correlate these beds with strata in other localities, although 
^ Texas Geol. Surv., 2nd Ann. Rep. p. 398. 
^ Texas Geol. Surv., 2nd Ann. Rep. p. 400. 
