TO JUNCTION OF GRAND AND GBBBN III VERS. 



91) 



General section of the Valley of the Colorado. 



No. 



1 



2 





Strata. 



Feet, i Formation. 



\ 



7 

 8 

 9 



10 



11 



12 



13 



11 



16 



16 



17 



Suit, yellow sandstones, alternating with gray, purple, and green- 

 bin marls, containing silloified ooniferons wood 



Dark bitnmino-oaloareous shales, with concretions and thfa bands 

 of compact blue liiucHtono weathering yellow. Fossils in the 

 upper part, immediately beneath No. 1, Ammonites placenta, 

 BaouUtes anoeps, Aporrhais NetoTwrryl, &c; toward the lower 

 part, Inooeramus, Nautihu, Oxtrea oongesta, fish-soafos 1,200 



Gray or dark-brown shales, with bands of dove-colored limestone 



weathering white, and thin layers of brown sandy limestone. 



Fossils: (h-jiphna I'itcheri, liioeenimitH problematic)!*, I. J'rtujilix, 

 Ammonites jxrear'uintiis, A. Macomln, Oxtrca luyubrix, (). niiiformis, 

 I'tyehodus \\l)i}>plei, I.ainna Te.rtina, &C - 



Coarse, yellow sandstone, sometimes interstratitied with beds of 

 shale and lignite. Fossils: Leaves of angiospermons plants, 

 Salix, Qucrc)i8, Ac 



Green and gray shales, and soft green or yellowish sandstones or 

 conglomerate 



Red and green shales, with bands of soft, white, red or greenish 

 micaceous sandstones. Fossils: Saurian bones and silieitied 

 wood 



Red, yellow, or white massive calcareous sandstone. No fossils 



Red, thin-bedded sandstones, with red shales. No fossils 



lutl and brown massive sandstone, line-grained, not hard. No 

 fossils 



Soft red sandstone, in thin layers, separated by beds of red or dark 

 brown shales 



Greenish-gray micaceous conglomerate and gray sandstone, sepa- 

 rated by red and purple shales 



Soft, liver-colored sandstones, becoming, suddenly and locally, 

 nearly white", with partings of shale 



Brick-red massive calcareous sandstones, with some like the bust... 



Hlne limestone, somewhat eherty. Fossils : Spii'ifer cumeratiis, 

 Athgris xiibtilita. I'rodiietus scmircticulatus 



(500 Cretaceous. 



do 



150 do 



Loealil v. 



250 



200 



350 

 550 

 150 



270 



360 



92 



350 



Kit 



.... do 

 .... do 



Jurassic .' 



Triassic. 

 ....do .... 



.... do 



....do 



.... do 



.... do 

 .... do 



11(1 Carboniferous. 



Bluish-white, rod, or mottled sandy limestone, with partings of 



red shale 



Hard bine eherty limestone. Fossils same as No. 14 j 36 



Alternations of blue limestone, red and gray sandstone, to bottom | 

 of canon j 1,000 



....do 



....do 



Mesa Verde. 



Do. 



Sage plain. 



Do. 

 Edge of Sage-plain. 



Canon Pintado. 

 Do. 



Do. 



Colorado Canon. 

 l>o. 

 Do. 



Do. 



Do. 



Canon of 

 Kiver. 



Do. 

 Do. 



Do. 



i .land 



Finding it impossible to pass down in the vicinity of the Colorado to its junction 

 with the San Juan, we wore compelled to retrace our steps, and again ascending to 

 the Sage-plain, crossed southwardly over its western extremity, along the eastern base 

 of the Sierra Abajo, to the San Juan Valley. This part of our route afforded us little 

 that was new in any department, and need not, therefore, long detain us. We found 

 the structure of this portion of the Sage-plain precisely like that before passed over. 

 The Lower Cretaceous sandstones everywhere form the surface-rock, except, where 

 covered with the overlying shales. The fossils of these shale-beds are often thickly 

 scattered over the surface, as in man)' localities enumerated on the preceding pages. 

 The plateau is here, as farther eastward, more or less broken by the canons of the 

 draining streams. These head in the Sierra Abajo and progressively deepen until they 

 terminate in the eroded valley of the San Juan. At various points along this part of 

 our route we saw ruins of ancient buildings, similar in character to those on the 

 Dolores; and fragments of broken pottery, an equally characteristic record of the 

 Pueblo race, were everywhere met with. 



Sierra Abajo. — Our near approach to the Sierra Abajo, while skirting its northern 

 and eastern bases, gave us a better knowledge of its extent and structure than we had 

 before obtained. The impressions we then received of it are given in the following 

 extract from my notes: "August 30, Camp 31, Mormon Spring, Our last cam]) was 



