34 



GEOLOGY OF THE YELLOWSTONE NATIONAL PARK. 



the mountain. Eastward the cherty beds have been removed from the 

 bench, and the white beds of Quadrant quartzite are exposed. 



On the summit of the 9,100-foot hill a small outcrop of the red and 

 yellow sandstone (No. 38 of section below) is exposed. West of this hill is 

 a deep cut, into which the small drainages of this part of the summit flow. 

 The surface of the area covered by the red beds is generally smooth and 

 grassy; the shales are exposed in cuts, but appear only as detritus on the 

 summit. 



On all sides of the mountain the white beds of Quadrant sandstone 

 form an escarpment, often capped by the cherty limestone. This Teton 

 cherty limestone varies greatly in character. Often it is a cherty sandstone 

 with little if any calcareous material in it; again it is a true limestone; and 

 these two extremes grade into each other. The chert seems to be formed 

 of sand, for the transition between the sandstone and the chert is often very 

 gradual. The color is a grayish brown. 



Crow- 

 foot 





sec- 

 tion. 



Sum 

 ber. 





39 



38 





38 



37 





37 



36 



G 



s 



36 



35 





35 



34 





34 



33 







32 

 31 



30 

 29 

 28 

 27 



a 







z- 



33 



26 



25 

 24 



23 

 22 

 21 







[20 



Section of beds exposed at the southeastern end of Quadrant Mountain. 



Feet. 



Sandstone, red and orange colored, coarsely granular, weathers in blocks 15 



Calcareous shale, dark slate colored, fossiliferous • 5 



Limestone, bright yellow, fissile, with platy debris, grading into yellow and red 



spotted calcareous sandstones below 40 



Shales, light greenish drab, changing to red and grading into overlying beds 75 



Conglomerate of red and gray quartz pebbles in limestone matrix 10 



Cherty sandstone, the lower part without chert, is brown; slightly calcareous at 



base, becoming more so above 100 



Limestone, dense, white, weathering same color 10 



Sandstone and limestone in alternating bands 15 



Limestone, light gray and dense and pure 12 



Quartzite, pure while, thin bedded, forms a persistent band along face of mountain.. 6 



Quartzite, more thickly bedded, white 65 



Limestone, very light gray, somewhat dense, containing very small fragments of 



light-colored chert 10 



Quartzite, white, calcareous, with intercalated bands of limestone carrying quartzite 



fragments 30 



Limestone, light gray, with angular fragments of sandstone 5 



Quartzite, white, weathering pink and rust color, but appearing black when seen 



from a distance, owing to the growth of lichens upon it 130 



Limestone, light gray, dense 2 



Sandstone, well banded, white, saccharoidal 6 



Sandstone, very calcareous, saccharoidal, white and rust color 10 



Talus slope of sandstone blocks ; also of cherty limestone 100 



