GEOLOGICAL SUEVEY OF THE TEERITOEIES. 157 



sent almost vertical sides like tlie bluffs along tlie Missouri Eiver. These 

 liills show first lower cretaceous shales, from one hundred to one hundred 

 and fifty feet thick, then fifty to one hundred feet of sandstone, the coal 

 beds overlaid with sandstones again. When any of the little streams cut 

 these beds, they reveal the coal, as in the Vermejo Creek and others, 

 ascending toward their sources. 



Near the Vermejo Creek I obtained the following general section 

 ascending: 



1st. Cretaceous shales, with Inoceratrtus and Ostrea. 



2d. Massive heavy bedded sandstone, yellowish gray, rather concre- 

 tionary in its structure, and weathering by exfoliation. 



3d. Three thin seams of coal, with clay above and below, in all twenty 

 feet in thickness. 



4th. Eusty gray sandstones, fifteen feet. 



5th. Clay, passing up into a thick bed of coal, apparently from six to 

 ten feet thick. 



6th. The coal is overlaid immediately by a soft sandstone, which passes 

 up into a heavy bedded sandstone, fifty to eighty feet thick. 



7th. One hundred and fifty feet of arenaceous clays, two beds of coal 

 about midway, one twelve inches the other four feet thick, with a few 

 thin beds of sandstone. 



8th. Capping the hills is a bed of sandstone of indefinite thickness. 



In the sandstone are immense rounded masses of a deep, dull reddish, 

 rather fine-grained sandstone, which is evidently concretionary. Many 

 of these masses have fallen down on the sides of the hill, and are now 

 disintegrating by the process of exfoliation. From these high hills one 

 can look with a field-glass fifty to one hundred miles into the plains 

 southeast, along the valley of the Canadian Eiver. A long, mesa-like 

 ridge extends down from the mountains and finally dies out in the 

 plains. I am confident that the conicar hills on the north side of the 

 Yermejo are six hundred feet above the bed of the creek. 



I am now satisfied that these tertiary strata extend close up to the 

 mountains from the Spanish Peaks to Maxwell's, and the only way I 

 can account for the very slight disturbances of the sedimentary beds is 

 the fact that the mountains to the west of them are mostly basaltic. 

 The miners in the Moreno Yalley regard it as very strange that gold 

 mines and coal beds should be found in the immediate vicinity of each 

 other. From the fact that these hills or mountains are composed 

 almost entirely of horizontal strata of comparatively recent date, I 

 think they should be called simply hills. They occupy quite an 

 extensive area, and contain a vast quantity of coal and iron 

 ore, practically inexhaustible, however great the demand in future 

 years. The brown iron ore of this vicinity is the richest I have 

 ever seen in the West, and the coal is equal to any ever discovered 

 west of the Missouri river, except that in thePlaciere Mountains of New 

 Mexico. Between the Cimarron and Eayada Creeks, a lofty ridge, one 

 thousand feet or more in height, extends from the mountains with a 

 trend a little south of east, the dip north about forty-five degrees. North 

 from this ridge, w^hich is composed of altered sandstones, the tertiary 

 beds dip gently about five to ten degrees. P>etween these and the al- 

 tered sandstone ridge is a cretaceous ridge, five hundred feet high, in- 

 clining at a moderate angle. This ridge of altered sandstone seems to 

 be a sort of side elevation or spur, j)rolonged eastward from the main 

 range, and soon ceases. 



From Maxwell's to Fort Union the plain country is occupied by creta- 

 ceous rocks, mostly the dark shales of No. 2, though the sand- 



