66 SURVEY OF COLORADO AND NEW MEXICO. 



and tliat the remaining sedimentary beds are composed of carboniferous 

 and possibly some permian exists in this region. 



Tlie carboniferous fossils are nnmistakable, and I think 1 have collected 

 some permian-like forms, and I suspect that my collections will furnish 

 the evidence of the age of the upper series of red beds as Jurassic. 

 The dip of all these beds is slight, not more than live to eight degrees. 

 From the old Pecos church to the Apache Cahou, ^Ye pass over the beds 

 of the lower red series, mostly consisting of sandstones and line pudding- 

 stones. But in Apache Caiion, we have a good exhibition of the fine- 

 grained, light-colored sandstones, which have cai)ped the mesas on our 

 left for thirty miles or more. So far as I could determine, this sandstone 

 does not belong to the lower cretaceous, but the true cretaceous ridge is 

 still further east. The incliuation of the strata in Apache Canon is 

 sometimes twenty-five degrees southward. 



As we commenced the ascent of the mountains towards Santa Fe, the 

 surface is covered with a remarkable conglomerate, a i^aste of sand ar.d 

 clay holding fast unworn masses of reddish granite. I think that this 

 is a modern formation, and underneath it we find the dull x)urijlish- 

 brown sandstones. I did not notice the carboniferous limestones on 

 the east side of the range, but do not doubt that they exist high up on 

 the mouutaiu sides. From the summits of the mountains we can look far 

 southward. All the ridges of upheaval continue southward along the 

 flaidvS of the mountains, and soon run out in the plain, and the moun- 

 tains slope down to the prairie about twenty miles south of Santai Fe. 



About thirteen miles before reaching Santa Fe, we come to the gneis- 

 soid rocks, and they continue nearly to tliat place. They seem to dip 

 with the sedimentary rocks on each side, only at a higher angle. This 

 mountain forms a regular anticlinal. On the flanks of the mountains, 

 (west side,) there is quite a thick deposit of yellow and light flesh-colored 

 marls and sands extending westward toward the head of the Rio Grande, 

 and beyond. The mountains themselves seem to be quite peculiar, in 

 being composed of an aggregate of cone-like peaks of very variable 

 heights. They seem to be entirely composed of gneissoid rocks. 



CHAPTER VI. 



FROM SANTA Fl5 TO PLACIERE MOUNTAINS AND RETURN. 



From Santa Fe to the banks of the Gallisteo Creek, eighteen miles, 

 we pass over the recent marls and sands which seem to occupy the 

 greater portion of the valley of the Rio Grande, above and below Santa 

 Fe, which I have called Santa Fe marls. These are mostly of a light 

 cream-color, sometimes rusty yellow, and sometimes yellowish white, 

 with layers of sandstones, varying in texture from a very.fine aggregate 

 of quartz to a moderately coarse pudding-stone. These marls and sands 

 weather into unique forms north of Santa Fe, like the " bad lands" or 

 " Mauvais Terres " of Dakota. As we descend the hill into the A^alley of 

 the Gallisteo Creek, we have a wonderful exhibition of the variegated 

 sands and sandstones, which at first appear like the upi^er series of red 

 beds on the east side of the mountains, but which I at once suspected 

 were new to me in this region. Descending the Gallisteo, to the west or 

 lower end of the Cerillos, we find the full series of the cretaceous beds, 

 with Ostrea congesta^ 0. larva ylnoceraimis — several species, and fragments 

 of fish remains. Extending east and west along the south side of the 



