48 CARBONIFEROUS FORMATIONS AND FAUNAS OK COLOKADO. 



(•ri'(lil)l(' jiuliiiucnt. As ;i rule (lie I'driiiiitioiis in tlit' (iruiid ( "aiiyon arc \('i-y iiiucli 

 thiiincr tliiin those of the Wasatch Mouiitiiins, und are coniparalile rathei- to those of 

 (■(Mitral ('oh)ra(lo, M-h(>re an almost precisely similar succession of beds has been 

 made out. 



In ISTS was published a r(>port by C. A. White" upon an ai-ea in nortlnveslcrn 

 Cohjrado >\ iiose limits he describ(>s in these words; ''The district upon which the 

 followiny- i-eport is made is included within th(> following- boundaries: The eastern 

 boundary is approximatel}' upon a straight line drawn from a point where the 

 meridian of longitude 107° 50' west from Greenwich crosses White River t(^ where 

 the meridian of 107^ 25' crosses Yampa River. The northern boundary is tiie iiarailel 

 of north latitude 40° 30'; the southern is the channel of White River, and the western 

 the meridian of 109° 30'." (Page 5.) Regarding this area he goes on to say: "The 

 districts surrounding the one here reported upon have, within the last few j'ears, been 

 geologically surveyed l)y different persons. That which adjoins it upon the west 

 . has been reported upon by Professor Powell in his ' Geolog}- of the Uinta Mountains.' 

 A geologic map of the district which adjoins this one upon the north has been 

 prepared by Mr. Clarence King during the progress of the United States Geological 

 Survej^ of the Fortieth Parallel. Reports to be published simultaneouslj^ with this 

 ai'c in preparation by the other geologists of the United States Geological Survey of 

 the Territories on the other districts which adjoin this one." (Page 20.) This state- 

 ment has the appearance at least of being somewhat erroneous, as the maps of both 

 King and Powell coA'er pei'haps the greater portion of the area surveyed by White, 

 and both l)ound it upon the north and west, but principally upon the north. 



White recognizes the following Paleozoic divisions, named in descending order: 



"No. 11. Tipper Carlxmiferoim. — Irregularly bedded light-yellowish sandstones, 

 with occasional calcareous layers, the sandstone layers often containing masses and 

 nodules of chert. Thickness about 600 feet. 



"No. 12. Middle Carl/on iferous. — Compact bluish fossiliferous limestone, heavily 

 or thinly bedded, alternating in some places with strata that are sandj' and ferrugin- 

 ous. Thickness about 1,000 feet. 



"No. 13. Lower Carhan iferous. — Massive layers of limesfone alternating with 

 those of sandstone and sandy limestone, all more or less ferruginous, generally pre- 

 senting a reddish-brown aspect, and all usually regularly bedded. Thickness about 

 1,500 feet. 



"No. 14. Uinta sandstone. — Massive or thinlj- bedded brick- red or more usually 

 brownish-red sandstones; usually hard and often quartzitic. Thickness, exposed in 

 this district, orAj about 400 feet; but the group reaches a thickness of nearly or 

 quite 15,000 feet in the Uinta Mountains only a few miles from this district." 



Though for No. 14 of this section White uses the name "Uinta sandstone" in 

 the extract above quoted, he elsewhere adopts from King the name "Weber quartz- 



1 V. S. Geol. Geog. Snrv. Terr., Tenth Ann. Rept., for 1.S76, pp. 3-liO. 



