SUEVEY OF COLOEADO AND NEW MEXICO. 59 



About due west of the fort is a long ridge which, runs nearly north 

 and south, and is underlaid by the quartzose sandstones of IsTo. 1. This 

 ridge is cut through in every direction by dry creeks, which show that 

 the strata are quite horizontal. The plateau or mesa-like summit is 

 about five miles across, when we descend into a park-like area eroded 

 out of the brick-red beds in the Cayote Valley. The rocks of the plateau 

 are here seen to incline east from five to ten degrees, just revealing the 

 upper portion of the brick-red beds. This valley is about three miles 

 wide and perhaps five to ten miles in length, and at the south end the creek 

 cuts through the cretaceous plateau, forming a narrow gorge. On the 

 west side we have the red upheaved ridge well shown, and all through 

 the valley are fragments of low ridges inclining at moderate angles. 

 Between the little branches of the creek and all around the borders of 

 the valley are well defined terraces. This valley or park is beautifully 

 grassed over, and the benches or terraces are as smoothly rounded off 

 as they well can be. The surface is covered with water- worn bowlders 

 and drift. On the west side of this valley the road passes through the gorge 

 of the Mora Creek, and for nearly ten miles we travel across the upturned 

 edges of the sedimentary rocks. There seem to be here two well defined 

 series of red sandstones; the upper series we have described as under- 

 lying the park-like valley of the Cayote Creek, about three miles wide, 

 and separated by loftj^ ridges of yellowish, gray sandstone on the east 

 side; and then, west of the gorge, a second series of rather dull 

 purplish or dull brick-red sandstones, all inclining in the same direction 

 but at different angles. The low ridges of the upper series of red beds 

 incline west fifteen, twenty, and thirty degrees. The highest ridge is 

 composed of the yellowish gray sandstone that separates the two series 

 of red beds, and is about one hundred and fifty feet high, and inclines 

 thirty-three degrees. 



Passing up the valley of the Mora the sandstones are of all colors and 

 textures, some of the ridges very fine, compact ; others coarse-grained, 

 and yielding readily to atmospheric influences ; others com^josed of an 

 aggregate of i^articles of quartz and small water- worn x^ebbles. Among 

 the pebbly sandstones there is a thin layer, perhaps a foot thick, of an 

 ashen-gray brittle limestone. This second or lower series of reddish 

 sandstones extends nearly two miles, dipi^ing fifty to sixty degrees; in 

 a few cases nearly vertical. The intervals between these ridges, which . 

 are usually from ten to one hundred yards wide, are grassed over and 

 sometimes reveal the fact that they are underlaid by soft shale. Neither 

 in the first or second series of red beds was I able to detect any organic 

 lemains. 



Within about three miles of Mora Yalley we come to a series of alter- 

 nate ridges of sandstones, limestones, and shales, inclining forty to fifty 

 degrees. The first bed of limestone is full of fossil shells, Productus, 

 several species, Spirifera suhtilita, S. triplicata^ &c. Then comes a bed 

 of micaceous sandstone, full of vegetable impressions of the genus 

 Calamites, and large fruits or nuts. These beds incline sixty-five degrees. 

 After this comes a coarse reddish sandstone, an aggregate of particles 

 of quartz and worn pebbles, most of it a fine pudding-stone. Then comes 

 about three hundred feet of reddish sandstone, then cherty limestone, 

 with Productiis, iSpirifera, and other species of true carboniferous types. 

 Alternate beds of sandstone, limestone, and shale continue nearly to the 

 Mora Valley — the beds of sandstone forming about nine-tenths of the 

 thickness. From Fort Union to Mora, eighteen miles, we pass directly 

 west, at right angles, to the mountain ranges, and over the upturned edges 

 of the sedimentary beds from the lower cretaceous to the metamorphic 



