p^^j^j.^ GEOLOGY EAST EIVER VALLEY. 249 



sedimentary beds curves in toward the northward, and then back toward 

 the south, and crossing Taylor Eiver turns gradually toward the north 

 around the granite point just south of the Triangle. The general dip 

 seems to be north and northwest. This entire region is one of great 

 interest, and to be worked up in detail will require some time. I can 

 hope to give only the most prominent features. 



Below the mouth of Cement Creek, East River flows through a beauti- 

 ful broad valley, in which it has cut well-defined terraces in the drift. 

 On the south side, some distance back from the river, are two mount- 

 ains, with mesa like summits. They were not visited, but they are un- 

 doubtedly capped with^ trachyte, as is a high hill on the north side, 

 which was ascended by Mr. Taggart. It is composed of a light purplish 

 trachyte. This rock extends to the eastward and southeastward, and 

 is probably continuous into Dr. Endlich's district. Above Cement Cieek 

 the river flows through a broad open valley, on either side of which 

 the Cretaceous formations are exposed. I will refer to this valley again 

 further on. Leaving the valley of East Hiver we proceeded up Cement 

 Creek, which, near the mouth, is in a caiion. The first exposure of 

 sedimentary rocks is on the west side, near the mouth of the canon. 

 Here are white and rusty sandstones, dipping about south 65° west, 

 inclination 15°. These sandstones probably belong to the Cretaceous 

 No. 1. Farther up the creek vre meet with dark and rusty-colored lime- 

 stones, which I think are unconformable to the sandstones near the 

 mouth, and belong to a lower horizon. They will have to be traced to 

 the westward before their exact relation can be determined. The dip 

 here is about north 45° west. Farther up stream, below these lime- 

 stones, are beds of quartzite, which rest immediately on the granite. 

 They are i)robably Potsdam. The dip gradually changes, and about 

 three-quarters of a mile up the caiion it is north 5° west, angle 10°. 

 The course of the creek here is south of west. The cafion for about two 

 miles has a comparatively wide valley, reaching to the base of cliffs 

 on either side. Above this point the canon narrows, and the trail has 

 to make a wide detour. Just at the point where the creek enters this 

 caiion the sedimentary beds cross almost at right angles to the course 

 of the stream. The dip here is about north 15° east, angle 20°. Above 

 this point the creek flows through a beautiful grassy valley, in which 

 all the beds are covered until we have gone about a mile and a half up 

 stream, when we come to beds of conglomerate with a red matrix con- 

 taining pebbles of limestone and granite. These seem to be somewhere 

 near the line between the Carboniferous and the Triassic (?) formations. 

 Above it are red sandstones. The dip of these beds is, toward the 

 northeast angle, 10° to 15°. Leaving Cement Creek at this point, we 

 crossed to Deadmau's Gulch, striking one of the northern branches, 

 down which we proceeded until we reached a fork coming in from the 

 north. At the head of this the red-beds are tipped up, and dip about 

 south 35° west, at an angle of 25°. This change in the dip seems to 

 have been caused by the upheaval of a high point to the eastward, 

 which I took to be volcanic, judging from the c/eim in the creek heading 

 under it. I was unable to visit it for want of time. Following up the 

 main Taylor Creek we find that the layers we saw crossing the east 

 branch of the creek still continue, the strike being toward the north- 

 west. One of the dikes (Layer ISTo. 4 in the sectioii) is very prominent. 

 Whether the other continues or not 1 could not determine. At the 

 head of the creek there is some confusion in the beds. On the west 

 side of the creek are high blufts of limestone, on top of which there 

 is a conglomerate sandstone. Below these beds, near the creek, is 'a 



