GEOLOGY OF THE LARAMIE PLAINS 



1 5. Gray sandstone. 



16. 16 feet of shales. 



1 7. 4 feet of gray shales. 



1 8. 75 feet of red beds. 



19. 1 foot of gray beds. 



20. 1 1 feet of red beds. 



21. 5 feet of gray ripple-marked sandstone. 



22. 12 feet of soft red shales. 



23. 11 feet of gray sandstone. 



24. 22 feet slope to railroad station. 



In above sections 1 and 2, Dakota 1 00 feet 



Nos. 3 to 17, inclusive, are Jurassic 2,201 feet 



Nos. 18 to 24 are Triassic 77 feet 



Although no fossils have been found as yet in the Triassic 

 of the West, yet its thickness, well developed, and its uniform red 

 beds cause it to be easily recognized. I have seen it on the 

 Colorado River in Texas, in Nevv^ Mexico, and at the Garden 

 of the Gods in Colorado, where it forms such curious figures 

 and stands on edge, forming spires over 200 feet high. Here 

 it is largely pebbly. It is often beautifully ripple-marked and 

 often contains beds of gypsum. On the southern border of the 

 Laramie Plains, I observed 36 feet of white gypsum with about 

 1 ,000 feet of red beds above and yellow beds below. Near 

 the Grand Caiion of the North Platte, ther.e are undoubtedly 

 several hundred feet of Triassic, including the bright brick-red 

 strata, some of it beautifully ripple-marked. At its base are shaly 

 beds with numerous chalcedonic concretions. Some of these, if 

 cut and polished, would form beautiful, agate-like ornaments. 

 Below this was observed about 40 feet of drab and buff lime- 

 stone, containing in the upper part numerous minute geodes. 



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