44 EXPLORING EXPEDITION FROM SANTA Ffi 



, Feet. 



25. Gray shale -_-.- 2 



26. Ferruginous sandstone 3 



27. Gray shale 7 



28. Dark-red or coarse gray sandstone, with obscure impressions of Lcpidodcndra 



and Sigillaria 



29. Gray and red shales, or indurated clays 5 



30. Dark-red ferruginous limestones, with nodules of red chert 15 



31. Grayish-blue 01 reddish silicious limestone, rather massive, without fossils. . 30 



32. Compact crinoidal limestone, reddish or gray in places, made up of bodies and 



stems of crinoids, the latter often large; also containing fish-teeth, spines 

 of Arcliccocidaris and great numbers of Prodiidus nodosus, 1\ Itoycryi, 

 A tliyris stiltlUta, Spirifvr cameratus, &c 25 



33. Dark-red ferruginous sandstone, sometimes a conglomerate and quartzose, in 



other localities soft and coarse 10 



34. Red, blue, green, and yellow, and mottled indurated clay, with nodules of . 



jaspery chert at bottom 18 



35. Cherty concretionary limestone, gray, yellow, blue, red, and contains a few 



Spirifers of an undescribed species 35 



36. Foliated silicious limestone, gray, yellow, or mottled, with dendritic man- 



ganese in the joints; no fossils; like the last, frequently a handsome marble. - 20 



37. Red massive granite to base. 



In the preceding section bed No. 1 is certainly not a member of the Carboniferous 

 series, but is probably the base of the Triassic formation. It is, however, less coherent 

 and of lighter color than any of the lower members of this group as they appear when 

 exposed near Santa Fe. It is conformable to the rocks below, while the Tertiaries of 

 that vicinity are, I believe, always un conformable. It will be seen that in this section 

 well-known Carboniferous fossils are found within less than 50 feet of the granite. It, 

 therefore, the older rocks are represented here, they are restricted to a portion of that 

 limited space. Without positive evidence to the contrary, I must regard all the rocks 

 of the section, except bed No. 1, as Carboniferous, and as the equivalents of the upper 

 division of that great formation; that is, the Coal-Measures. As before remarked, in 

 the walls of the canon of the Great Colorado is a limestone mass, lying beneath the Coal- 

 Measure limestones, which I have supposed might be the Mountain limestone; but of 

 whatever age, that rock and the strata which underlie it are here wholly wanting. 

 There are doubtless some geologists who will regard the granitic base of the preceding 

 section as a metamorphosed condition of the sedimentary rocks which are here due 

 beneath the Carboniferous strata; but this view of the case seems to me wholly unten- 

 able. The massive, unstratified, red granite of the Santa Fe Mountains presents char- 

 acters, both iri its physical structure and chemical composition, which could never be 

 assumed in any possible phase of metamorphism by the older Paleozoic rocks of the 

 Colorado Canon. Much the greater part of their mass is calcareous, and only the 

 extreme upper and lower portions are red. Again, the lower members of the scries of 

 sedimentary strata at Santa Fd are but slight!}', if at all, metamorphosed. Even if 

 those which rest on the granite in the preceding section be supposed to be changed from 



