52 GEOLOGY OF THE DENYEK l'.ASIN. 



on the west and a ridge of Dakota quartzite <ir sandstone on the east. 

 Rising from the valley bottom are lofty, cathedral-like spires of vertical or 

 highly inclined strata, brilliant in coloring, and producing by contrast with 

 die green of vegetation effects most picturesque. In the northern portion 

 of the field these effects still prevail, but the lower half of the Red Beds 

 rises high upon the mountain slopes, forming prominent peaks along the 

 range-front. 



The formation is separable about midway into a lower division, of soft, 

 friable conglomerates and coarse sandstones, with lew shales, and an upper 

 one of shales, with some prominent sandstone bands, narrow beds of lime- 

 stone, and small local deposits of gypsum. The following section, taken at 

 Morrison, is typical, reading from top downward: 

 Section of ilorrison, Colo. 



UPPEB DIVISION. 



Feet. 



Sandstone, fine-grained, often massive, pink and brown; 

 persistent • •"• '" 25 



Clays, bright-colored— gray, yellow, green, pink, ami 

 lilac; gypsiferous and calcareous, especially 40 feel 

 below their summit 125 to 17"> 



Clays, more arenaceous than above: transitional in 

 color, from grays, etc., above, to prevailing brick- 

 reds below toO to 200 



Sandstone and shale, alternating': brick-red to pink; 

 white dots: sandstones prominent 50 



Sandstones and shales I'll 



Shales, sandy and argillaceous, brick-red, carrying nar 

 row bands (3 to 6 feet) of white crystalline limestone 75 



LOWEB DIVISION. 



••Creamy'* sandstone: ipiartzosc: conglomeritic at base; 

 two sandy limestone bands in lower part; round fer 

 ruginous concretions near lop: forms prominent out- 

 crop in valley between Archean and Dakota (average 

 250feet).... 200 to 400 



Red Beds; conglomerates, sandstones, and shales, the 

 last of minimum development; color, red: outcrops, 

 lofty spires and pinnacles and towering masses of 

 irregular shape 270 to 2, 000 



