88 GEOLOGY. 
villages, we saw none but Cretaceous strata, sandstones, shales, and beds of lignite precisely 
like those at Moqui. Then, however, we came on to a series of strata very different in 
character from any seen between this point and the Pacific, and such as I am inclined to believe 
are not represented in all the region bordering the first half of our route across the continent. 
These I have supposed to be fresh water Tertiaries, probably of Miocene age, parallel to those 
of the ‘Bad Lands”’ of Nebraska. They fill a depression in the Lower Cretaceous rocks, and 
occupy a space of several miles on our route, forming a basin, of which the northern and 
southern limits are not yet determined. 
The prevailing color of the beds is white or light ash, and cream color. They possess little 
consistence, and have been, by atmospheric erosion, cut into pyramids and pinnacles of as 
varied and peculiar forms as those of the Mauvaise Terre. Unfortunately, we were compelled 
to hasten over this interesting district so rapidly that I was unable to make the search necessary 
to discover fossils in this formation. 
The lithological character of these rocks will be seen from the following section : 
1. Reddish brown marl, forming summit of hiils. | 
2. White and light ash-colored marls, with thin layers of sandy, cream-colored limestone, 
200 feet. 
3. Light brown marls, 100 feet. 
4, Coarse reddish yellow sandstone, Cretaceous. 
SSS 
SNe ee 4 = 
Fig. 23.—MONUMENT IN ERODED VALLEY, NEAR CAMP 100. 
Near the eastern portion of this Tertiary basin we descended into an extensive and beautiful 
valley, eroded in the Cretaceous and underlying rocks. The bottom of the valley is a grassy 
plain, stretching far away to the north, and bounded in that direction by picturesque mesa 
walls, which rise above it to the height of eight or nine hundred feet. The sandstones here 
exposed of the Cretaceous and Marl series are of a chalky white or greenish yellow, and in the 
erosion of the valley a number of isolated buttes have been left, resembling in their forms 
