THK CARHONIKEUOIIS 1»LATEAU. 



11 



are to bo found in the deeper of the canons. On Inyjin Kara Creek, and 

 especiall}- on lieduater Creek and Heron Creek, tiiey are readily 

 examined The acconipanyino- ideal section, rnnninj^- from the lied Valley- 

 near Inyan Kara eastward across the pla- 

 teau to Custer Peak, a distance of thirty 



miles, tliou"h only ai)i)roximate in its de- 



P y f- ^ i-^ T' 

 tails, will give a tolerably correct idea of wxid^ijii 



the structure of the mesa at this point. ^"^ ^^§ 



'- c 5" s 5= 3 



Nearly the whole of the northern i)art -Xs ^^^-S 

 of the i)lateau bears at the surface either the tl.%v.%Z 

 silicious or the ""ray limestone (Nos. 2 and %%it%t 

 3 of the general section), and of the two the ' ^ § 

 gray limestone is more })rominently ex- 

 posed. Crook Tower consists probably of 

 the gray limestone with a capping of the 

 silicious, and fragments brought from its 

 body are filled with Spirifera.Rocky-montana. 

 Considerable portions of the limestones have 

 been removed by erosion from the sin-face 

 of the plateau and a greater amount at the 

 east than at the west. The silicious lime- 

 stone rarely appears in the cliff at the east. 



3 

 9 



o 



3 



o 



s* 



o 



O 





p P s e- 





and never with its full thickness, and there ^ 



f' _ ^ _ . 



are considerable areas covered by the jrray = = -5 ^ S 

 limestone exclusively. Opportunities for the 



2 

 p" 



full measurement of either member are rare 1 1.| 



£.2 



W 



Pi 



and are confined to the deep canons — 



especially to the canons of streams running 



eastward. The upper valleys of Inyan 



Kara and Redwater Creeks, running from 



south to north, are not of very great depth, 



and the edges of the bordering rocks are 



commonly in whole or part hidden in their sloping soil-covered sides. On 



the eastern side of the plateau, how^ev(;r, the northward flowing Spear- 



