FORMATIONS OF THE FRONT RANGE 



413 



Table of Paleozoic and Mesozoic formations of eastern Colorado 



Age. 



Formations. 



Principal characters. 



A verage 

 thickness. . 



f 



Denver 



Conglomerates, sandstones, 



and claj^s. 

 Clay on thick basal series of 



conglomerates. 

 Clays, with sandstone layers 



and coal beds. 

 Sandy shales, with sandstone 



at top. 

 Dark shales, with local sand- 

 stone layers. 

 Light colored soft limestones 



and limy clays. 

 Dark shales, with sandstone 



at top. 

 Slabbv limestones 



Feet. 

 1,450 



Tertiary -j 



Fox Hills 



800 



1,000 



100-1,000 



1,500-7,500? 



350- 700 



200 



30 





Pierre 



Cretaceous. . . - 



f 

 Carlile....] 

 Greenhorn > Benton ■{ 

 Graneros. . J 



I 



Morrison 





Dark shales, with local sand- 

 stone layers in lower part. 



Gray sandstones, sometimes 

 conglomeratic, fireclay in 

 middle. 



Gray to maroon "joint clay," 

 with limestone and sand- 

 stone layers. 



Soft sandstone and sandy 

 clay. 



Bright red sandy shales, with 

 thin limestone layers and 

 gypsum, reddish sandstone 

 at top. 



Coarse red sandstones and 

 conglomerates. 



Gray and purplish limestone. 



Gray to pinkish dolomite, 



uneven grain. 

 Fine, even grained, gray to 



pink sandstone, some shale. 

 Reddish dolomite 



400- 500 

 350 



200 



Triassic(?) and 

 Permian (?). 



Pennsylvanian. 

 Lower Missis- 



Comanche series 



Upper Wyoming 



(Chug water). 



Lower Wyoming 



(Fountain). 

 Millsap 



20 

 400 



600-1,200 

 30- 200 



sippian. 



Fremont 



100 



Ordovician. . . - 



Harding 



100 



Manitou 



100- 270 



Cambrian 





Reddish sandstone 



Granite and schists 



40- 100 



Algonkian and 

 Archean. 







CAMBRIAN 



Rocks of Cambrian age are exposed in the Manitou embayment west 

 of Colorado Springs and in a smaller area north of Canyon City. Else- 

 where along the Front range post-Cambrian rocks appear to lie directly 

 on old granites and schists. In the Manitou Park area there are about 

 100 feet of sandstones mostly of light color, containing upper Cambrian 



