DETAILS OF THE EED VALLEY. 141 



Bed Beds. 



Feet. 



2. Soft sandstone, blood red ; appears somewhat argillaceous 80 



1. Shaly sandstone, deep red, changing into red sandy shales, and below into 



red clay with gypsum (estimated) . . 200 



The transition from the red sandstones of the Red Beds to the soft 

 white sandstone and gray marls above is perfectly distinct. Gypsum is 

 seen in great abundance, and two seams have each a thickness of 8 or 10 

 feet. The locality affords a fine opportunity to study the infiltration veins 

 of gypsum. The sandy clay in particular is highly suffused, and a laby- 

 rinth of dry gulches with vertical sides from 10 to 30 feet high expose fine 

 natural sections. 



Our next local examination was made on Amphibious Creek twenty 

 miles east of .Red Canon Creek. The entire width of the valley, including 

 the slope of the limestone, is between four and five miles, and the red clay, 

 though well exposed, occupies but a narrow belt along the foothills. 



The following ideal section is in direct continuation of the section 

 already given in Figure 17 : 



65 4 34343 2 1 



Fig. 20. — Ideal section across Eed Valley on Amphibious Creek. 



1. Carboniferous. 5. Jura. 



2. Eed sandstones and clay (Eed Beds). 6. Cretaceous sandstone capping the foothills. 



3. Purple limestone (Eed Beds). 7. Clays of the lower Cretaceous. 



4. Eed clay with gypsum (Eed Beds). 



As rudely indicated in the wood-cut the limestone after dipping down 

 from the north side of the Red Valley warps up again in several places 

 along the creek. Near the pass of the creek through the foothills there is 

 exposed a stratum of gypsum 8 or 10 feet thick, lying 175 feet above the 

 purple limestone ; and elsewhere in the vicinity the same mineral shows 

 numerous outcrops. At the pass the following section was taken; it shows 

 again the character of the junction between the Red Beds and Jura, 

 though here there is no evidence from fossils : 



