46 EXPLOKING EXPEDITION FEOM SANTA FE. 



Section No. 3. 



Feet. 



1 . Greenish shale 10 



2. Soft greenish sandstone, including a band of ferruginous conglomerate, con- 



taining impressions of Lepidodendrq 16 



3. Gray marl, with nodules of blue limestone 6 



4. Yellow and mottled limestone, (a handsome marble) 10 



5. Blue, concretionary, cherty, silicious limestone, same as No. 35, section No. 1 . 50 



6. Shelly argillaceous limestone, (same as No. 36 of section No. 1) 16 



7. Yellow micaceous sandy shale, very soft 3 



8. Coarse, soft white sandstone, sometimes a conglomerate 5 



9. Red massive granite, to base. 



The other localities in the vicinity, where the Carboniferous strata are exposed, 

 are on the Sandia, Placer, and Jemez Mountains, and in the valley of the Pecos, at 

 and below Pecos Village. They underlie, it is true, almost all parts of New Mexico, 

 but are only visible on the flanks of the mountains and in some of the valleys, which 

 are cut through the overlying rocks. I had not an opportunity of obtaining a complete 

 section of the Carboniferous group on the Sandia and Placer Mountains, as only a 

 portion of the series is exposed in the localities which I examined. As far as 

 observed, however, they seem there to be but little metamorphosed, and contain many of 

 the fossils most characteristic of the Coal-Measure strata of Santa Fe and of the valley 

 of the Mississippi. At Jemez, the rocks of this age rest upon the opposite sides of the 

 red granite core of the mountain, are inclined at a high angle, and are highly fossil- 

 iferous. The features which they present there will, however, be described more in 

 detail in a succeeding portion of this report. 



The exposures of the Carboniferous strata, at and near Pecos Village, are of pecu- 

 liar interest, for, although the section which they afford is less complete than at Santa 

 Fd, the line of junction between the Carboniferous and Triassic series is more distinctly 

 marked, and the upper beds of the former group are more fossiliferous. The strata 

 forming the cliff at Pecos Village are the equivalents of the upper portion of the Santa 

 Fe" section, consisting of beds of limestone, separated by layers of shale and sandstone, 

 the former containing, as characteristic fossils, Athyris subtilita, Producing scmireticu- 

 latus, P. scabriculus, P. Rogersi, Spirifer cameratus, &c. The dip is here from the 

 mountains toward the south and east, and, near the old Pecos church, all the Carbon- 

 iferous series pass beneath the chocolate-colored sandstones and shales the base of 

 the Triassic formation and disappear. The upper member of the underlying group 

 is a brownish, rough, somewhat sandy limestone, of which portions are more purely 

 calcareous. This bed contains a large number of fossils, as far as observed, without 

 exception, such as are common in the Upper Carboniferous strata Permo-Carbonifer- 

 ous of Meek and Ilayden of Kansas. These are a Monotis, not well preserved, but 

 resembling M. Ilawni (and, perhaps, as much, another found in the Middle and Upper 

 Coal-Measures of Missouri and Kansas), Athyris subtilita f, the same found in the 

 Upper Carboniferous and Permian beds of Kansas, referred doubtfully to A. subtiUta 

 by Mr. Meek, and which is larger, broader, and more gibbous than what is known 



