SURVEY OF COLORADO AND NEW MEXICO. 49 



the various formations are sliown in a nearly horizontal position, or 

 inclining southwest at a small angle. Indeed, Oil Creek flows through 

 a sort of synclinal valley in part, and near the source of it the red or 

 triassic beds rest upon the granites. All along tliis creek, where the 

 unchanged rocks are well shown, the lower cretaceous beds seem to 

 pass down into a narrow belt of ashen gray sands and sandstones, which 

 continue down into a variegated series of beds, a part of w^hich I regard 

 as Jurassic. 



Near the oil springs there are, above the reddish beds, six layers of 

 massive sandstones, varying from ten to twenty feet thick, with seams 

 of arenaceous clays, from a few inches to ten feet in thickness. These 

 rocks exhibit all the indications of shallow water deposition in places, 

 but not a fossil of any kind could be found, and, therefore, it is dif- 

 ficult to determine whether they are lower cretaceous or Jurassic. 



As to the sources of this oil, I could gain no reliable information. The 

 borings have gone down into the pudding-stones of the lower triassic, 

 and yet no reservoir has been found. It is not known but that the oil 

 may come up from the granites. Great quantities of salt water issue 

 from the springs with the oil, and the oil is taken from the surface of 

 the salt water. 



At Caiion City, where the Arkansas comes out of the mountains, 

 on the south side of the river, the i)rincipal ridge or " hog-back," which is 

 composed of No. 1, dips 34°, and has a trend about southwest; while on 

 the north side the long ridge, of which there is a very high one, like a 

 lofty wall, composed of the sandstones of No. 1, while a lower outer ridge 

 is made up of the fine calcareous sandstones of No. 2, filled up v/itli 

 Inoceramus. It is from this low ridge that the stone for buikliug pur- 

 poses is obtained. It is not very durable, but works easily and makes 

 handsome structures. This regular wall extends northward, bordering 

 the plain in a straight line for five or six miles, and is very consi>icuous. 



Issuing from the ground, between the ridges of cretaceous No. 1 and No. 

 2, in the valley, about a mile above CaCou City, is one of the finest mineral 

 springs we have seen in the West. It is quite small, but the water is de- 

 licious. It is doubtless the same, essentially, as the springs at Colorado 

 City. 



Just back or inside of this sandstone wall No. l,is an ashen-gray bed 

 of arenaceous layers, with a bed of fine silicious limestone, containing 

 what seems to me to be indistinct fragments of fresh water shells. This 

 belt passes down into the red pudding-stones below. Passing u]) the 

 Arkansas a few hundred yardsfnrther, wecome to the metamorphic rocks. 



About four miles below Canon City, on the Arkansas Eiver, are some 

 isolated hills, looking in the distance like fortifications, composed of Nos. 

 4 and 5 cretaceous, capped with a rusty yellow sandstone, which I regard 

 as the lowest bed of the coal formations. 



Both the cretaceous and tertiary beds seem to dip southwest five to ten 

 degrees, while on the south side of the Arkansas the tertiary beds incline 

 rather northeast, so that there is an obscure synclinal which shows the 

 influence of the ranges of mountains on each side of the valley. The coal 

 strata have all the characteristics of the older tertiary sandstones, as 

 shown in the Laramie Plains. 



Between Canon City and Hardscrabble Creek, the tertiary beds jut 

 up against the Wet Mountain range, concealing all the older rocks. 

 About half a mile east of Caiion City, the high cretaceous ridges are seen, 

 and then they disappear beneath the tertiary beds, and reappear at the 

 head of Hardscrabble Creek, about thirty miles to the eastward. 



High up the foot of the granite hills of Wet Mountain, an obscure syn- 

 4 G S 



