48 EXPLORING EXPEDITION FBOM SANTA FE. 



shales — the "Saliferous group" of my former report; the "Bunter Sandstein" or lower 

 division of the Trias of Marcou. In the valley of the Pecos, both at Pecos Village and 

 San Josd, I obtained from the Lower Red Beds vegetable impressions, which, if more 

 perfectly preserved, would probably enable us to draw the lines of classification more 

 sharply than has hitherto been possible. As it is, they give us reason to suspect that 

 the lower portion of the Gypsum series should be regarded as of Permian age; and, 

 by proving that these strata are not entirely without fossils, encourage us to hope that 

 their place in the series may soon be accurately determined. 



The mesa bordering the valley of the Pecos on the south forms a part of the great 

 table-land which stretches away eastward from the base of the mountains, of which a 

 portion has received the name of the Llano Estacado. Except where cut by the valle}~s 

 it is continued throughout, and has, apparently, everywhere the same geological struc- 

 ture. The section afforded by its cut edge in the valley of the Pecos is as follows: 



Feel ' 



1. Yellow and brownish foliated sandstones with alternations of red, purple, and 



gray shale, forming detached buttes on the mesa, without fossils 200 



2. Yellow, massive sandstone, summit of cliff, without fossils 150 



3. Red, white, or green, soft calcareous sandstones and shales with gypsum, with- 



out fossils 800 



4. Red and green sandstones and conglomerates, separated by thicker beds of 



green, blue, and purple shales, with oxide of iron and copper, and with ferns, 

 Walchiaf and Catamites — - 200 



5. Limestones and sandstones containing Carboniferous fossils, to bed of stream. 



In this section I have supposed Nos. 1 and 2 to represent the Lower Cretaceous 

 sandstone group. No fossils were discovered in them in this vicinity, but on the banks 

 of Galisteo Creek, a few miles farther south, in the yellow sandstones which rest on 

 the red gypsiferous strata, I found the leaves of angiospermous dicotyledonous trees, 

 which prove them to belong to the Cretaceous system. 



No. 3 of the section is apparently entirely without fossils, and consists of a scries of 

 alternations of deep or pale red and white — rarely greenish — indurated marls or soft, 

 fine calcareous sandstones. No analysis has been made of these beds, but they prob- 

 ably contain as much sulphate as carbonate of lime. They are precisely similar to 

 the strata forming the upper of the two plainly-marked divisions of the Gypsum series 

 throughout Western New Mexico — what I have called in my former report the Varie- 

 (jatcd marls — and are distinguished by striking lithological characters from the 1 

 "Saliferous sandstone group" which underlie them, and form No. 4 of the section. 



This latter group is nowhere exposed in a section which could conveniently he 



measured, but its thickness is somewhere between 200 and 250 feet. A very good 



idea may be formed of its prevailing character from the following section taken at the 



village of San Josd; the first stratum being the highest: 



Peot. 



1. Coarse reddish or gray sandstone, frequently a conglomerate 8 



2. Chocolate-colored or greenish foliated micaceous sandstone shading into shale; 



containing a band of compact dark-gray silicious limestone, weathering 

 brown - 20 



