44 EXPLORING EXPEDITION FKOM SANTA FF 



I'.vl. 



25. Gray shale - 2 



26. Ferruginous sandstone 3 



27. Gray shale - 7 



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



and SigiUaria 8 



29. Gray and red shales, or indurated clays. 5 



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



31. Grrayish-blue Oi reddish silicious limestone, rather massive, without fossils . . 30 



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



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

 of ArcTkBoddaris and great numbers of Productus toodosus, P. Rogersi, 

 . I thyris subtlUta, Spirifcr cameratics, &c 25 



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



< »tlier 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 

 scries, but is probably the base of the Triassic formation. It is, however r 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 unconformable. It will be seen that in this section 

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

 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, unstratiiied, red granite of the Santa Fe Mountains presents char- 

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

 assumed in any possible phase of nietamorphisni 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 series of 

 sedimentary strata at Santa Fe are but slightly, if at all, metamorphosed. Even if 

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



