MORRISON SHALES OF COLORADO AND NEW MEXICO 57 
the exposures which I studied along the Canadian, and extends 
to within a few miles of the Rio Cimarron. According to Mr. 
Hill’s section the Lower Cretaceous, consisting of the Zvinzty, 
Fredericksburg, and Washita, lies between the Red Beds and the 
Dakota. If Mr. Hill’s section represents correctly the age of 
the formations in the Canadian valley, then the shales and 
possibly the Exeter sandstone must be of Lower Cretaceous age. 
But the shales, as I have already shown, are probably the same 
as the Dinosaur-bearing shales of the Purgatory. There is some 
probability therefore that the Morrison formation may be identi- 
calwith some patt of the: Lower Cretaceous of the Texas 
region. 
Correlation.—The key to the correlation of the shale for- 
mation is found in the Walsenburg area, Colorado. Mr. Hills? 
describes the Morrison of that region as a series of variegated 
shales, sandstones, and limestones lying between the Red Beds 
and the Dakota sandstone. According to his map the Morrison 
is found along the mountains near the western border of the 
Walsenburg quadrangle and in the canyons at the eastern 
extremity. The Morrison, as described in his folio, is identical 
in lithologic character and stratigraphic position with the shale 
formation described in this paper. In the Spanish Peaks area, 
bordering the Walsenburg area on the south,? the Morrison is 
also thought to be represented in the uplift at the Spanish Peaks. 
From the exposures mapped by Mr. Hills along the mountains 
it is but a few miles to the outcrops of the shale formation along 
the foothills previously described in this paper. The sedi- 
mentary formations, including the shales, are upturned a few 
miles west of the western boundary of the Spanish Peaks area, 
hence do not appear in the map of that region. There is little 
doubt that the shales which I have described as occurring as far 
south as Gold Creek, N. M., is a part of the southward continua- 
tion of the Morrison formation. 
Starting again from the Walsenburg area, the Morrison occurs 
™R. C. HILxs, U. S. Geol. Surv., Walsenburg Folio, Colo. 
?R.C. Hvis, UV, S. Geol. Surv., Spanish Peaks Folio, Colo. 
