GO CARBONIFEROUS FORMATIONS AND FAUNAS OF COLUKADO. 



Thifikness, 

 Ft. In. 



1 -. AVliite conglonieritic sandstoiu' 5 



l:i. Hoil conglomeritio sandstoni' - 38 8 



14. Dark-rod micaceous shaly saiulstnncs C 8 



1.'). P.nnvnisli-rcd sandstones,' conglonieritic 3f ID 



1(1. l-'ine-giaincd sandstone, generally white, but becoming pink in places, with two or three 



layers of gray micaceous shale, each from 2 to 4 inches thick 4 



17. Coar.'^e white sandstone, with grains of quartz and some decomposed feldspar 71 '■'> 



18. Soft greenish sandstone in fine layers, with a few hard bands, each a few inches in 



thickness 99 3 



19. Red sandstone 11 4 



20. Brownish sandstones 99 8 



21. White granular brown-spotted sandstone 8 



22. Greenish-gray micaceous sandstones, partially congloineritic ■. 352 



23. A space in which the lieds were so much concealed that it was impossible to make a 



detailed section; the upper portion is probably filled with a prolongation downward 

 of the micaceous shales and sandstones, while the base is limestone. In the latter I 

 loxmA Ariculopeciei-i , Pleurophor us, and nn Avicula or Bakevellia. The total thickness 

 of strata as indicated by the space is 408 4 



Total thickness of supposed Carboniferous 2, 504 20 



The remainder of the section to the beds I included in the Devonian? is as follows: 



Feet. 



24. A laminated trachytic rock 15 



25. Space probably tilled mainly by limestones "i 



^ ^ ■ ■ - ( a 1,000-1, 500 



26. Black, flinty limestone, with pieces of pyrite and fragments of Spinfer or Spinfenna) 



Section of Silurian strata on Eagle River. {After Peale.)^ 



Ft. In. 

 7. Light-bluish limestones on ^yeathe^ed surfaces, white and yellow. It is in bands from 



3 to 8 inches thick, with a cross fracture and nonfossiliferous. A great portion of 



these limestones are probably magnesian. At the top they are crystalline 219 6 



Calciferous group: 



6. Space, in the upper portion of which there is an outcrop of metamorphosed conglomerate, 



seemingl}' composed of pieces of white quartzite and brown sandstone. The masses 



are irregularlj' shaped. The outcrop is only a few feet in thickness and the remainder 



of the space is probably filled with sandstones and quartzites, with perhaps a few shales. 



The space was so covered that the beds were all concealed. The entire thickness is .. 68 4 



5. Milk-white quartzite, similar to that of No. 1 4 9 



4. Si^ace probably filled with sandstones 22 8 ' 



3. Grayish-brown laminated sandstones with a greenish coating and mud marks on the 



surfaces of the laminse 98 6 



2. Fine-grained, rather compact, glauconitic sandstone, somewhat laminated, dark brown 



and greenish gray 10 



Primordial group: 



1. Milk-white quartzite 400 



Gneiss: 



Total thickness of Silurian about 819 9 



t< Estimated. bv. &. Geo). Geog. Surv. Terr., Eighth Ann. Eept., Jor 1874, 1876, p. 11.3. 



