202 GEOLOGICAL SURVEY OF TPIE TERRITOEIES. 



older tbau Triassic. From No. 13 down all is Silurian. Perhaps the 

 limestones of ISTo. 14 should be referred to a higher horizon. Beds Nos. 

 2 to 5 I have referred to the Potsdam group, while those just above are 

 undoubtedly of the Quebec group, as in beds lithologically the same in 

 the western side of the range I found characteristic fossils. I found in 

 them Terebratula and Crania. In these beds, also in the Ute Pass, in 

 1869, Dr. Hayden found Ophileta complanata, Bucanella nana, (Meek,) and 

 other species, from which Professor Meek referred the beds to the 

 Calciferous division of the Lower Silurian.* The line of junction be- 

 tween No. 14 and No. 16 could not be seen, as it was covered with debris. 

 The massive red sandstones of No. 16 (No. 16 of section No. 1, and No. 

 1 of section No. 3) are here tipped 5° past the vertical, and the weath- 

 ering of these ridges has given rise to the peculiar forms seen in the 

 " Garden of the Gods," and which have been fully described in previous 

 reports. These sandstones have here the same general characters that 

 we have noticed all along the range. They are still coarse-grained, 

 giving evidence of their deposition in shallow waters. I was unable to 

 get the thickness of the beds, but estimated it, including No. 18 and 

 the space between, at about 1,000 feet. From No. 19 up to the bottom 

 of No. 37, we have the layers that I have considered as Jurassic. In the 

 gypsum bed (No. 30) I found some selenite and some fair pieces of satin 

 spar. Nos. 37 and 38 represent the No. 1 Cretaceous, while the space 

 just above, (No. 39,) which is in all probability filled with shales, be- 

 longs to the Fort Benton group. Bed No. 40 is filled with excellent 

 specimens of InoceramuSj while in No. 43 we have quantities of Ostrea. 

 This bed has the same bituminous odor on breaking that I noticed at 

 points farther north. The dip of these beds is about due east, at an 

 angle of 30°. This angle as we go down increases quite rapidly. At 

 No. 40 it is 550 ; at No. 38 it is 60°, and at No. 39, 65° to 70° ; below 

 this it decreases to 50°, and at No. 18 the beds are vertical, while the 

 red-beds (No. 16) are tipped past the vertical, as we have already seen. 

 Between Camp Creek and Monument Creek, a distance of about two 

 miles and a half, there is a drift-covered mesa, in which the beds are 

 entirely concealed. They belong probably for the most part to No. 4 

 Cretaceous, and perhaps the upper portion of No. 3. In the banks of 

 Monument Creek we find the upper portion of the black shales of No. 4. 

 In the bed of the creek, a few miles above Colorado City, we find a bed 

 of hard, bluish limestone, which is in thin layers, and contains Inocera- 

 mus and other cretaceous fossils. Above this there are brownish and 

 black shales, all more or less fossiliferous. Above the black shales we 

 have a thin layer of sandstone, containing Baculites and Ammonites. 

 Above this are sandstones. Above the cretaceous layers are the lig- 

 nitic beds. These have been studied by Professor Lesquereux, and I 

 refer to his reportt for the details. I will only insert here a section 

 made by him at Gehrung's coal-mine : 



1. Brown laminated fire-clay or chocolate-colored soft shale, a 



compound of remains of rootlets and leaves and branches 



of undeterminable conifers 2 feet. 



2. Coal, soft, disaggregating under atmospheric influence. . . 2 feet. 



3. Chocolate-colored clay-shaie, like No. 1, with a still greater 



proportion of vegetable debris 6 feet. 



4. Soft yellowish coarse sandstone in bank 8 feet. 



5. Clay, shale, and shaly sandstone covered slope » 130 feet. 



*Report 1870j United States Geological Survey, page 287. 

 tEeport 1872, page 335. 



