16 REPORT UNITED STATES GEOLOGICAL SURVEY. 



The drift materials are composed mostly of the rounded fragments of 

 such rocks as occur in the valley above and on the sides of the neigh- 

 boring mountain. 



On all parts of the slope, especially about the springs, there are very 

 numerous erratic fragments of indurated calcareous sinter that resem- 

 bles very closely an ordinary limestone. They are yellowish, compact 

 masses, with rough, scoreaceous-looking surfaces, and it was not until I 

 had made several attempts to liud fossils in them that I discovered that 

 they were of hot-spring formation, and that they had their origin in a 

 heavy stratum that occurs on the summit of a flat-topped hill that over- 

 looks the canon of the West Gardiner, and is separated from Sepulchre 

 Mountain by the depression through which the road passes. 



The drift, slide and hot-spring material that covers the greater part 

 of these slopes is underlaid by Lower Cretaceous and Jurassic rocks, 

 which rise from the bed of the river at the base of Mount Evarts with 

 a dip that corresponds approximately with the slope. They soon pass 

 beneath the rhyolites and conglomerates that constitute the upper part 

 of the mountain, excepting in the vicinity of the pass which leads from 

 the spring over the ridge south into the upper valley of the Gardiner. Here 

 the volcanic rocks have been eroded away and a small area of Jurassic 

 rocks is exposed. 



On the 10th of September I left camp at the springs and passed up 

 the drift-covered ridge to the north of the deep gorge at the mouth of 

 which McCartney's cabin is built. Snow had fallen to the depth of 

 three or four inches the night before and the day was cold. In the drift 

 there are fragments of basalt, quartzite, flinty limestone, and a peculiar 

 coarse conglomerate. The latter is doubtless derived from the break- 

 ing down of the conglomerates of the Dakota Group, which outcrops in 

 the steeper parts of the gulches about the springs. About half a mile 

 above McCartney's house there are a few ledges of hard calcareous sand- 

 stone which appear above the coarse avalanche debris and the heavy 

 deposits of vegetable mold. This sandstone I take to be Cretaceous 

 also. Just here occurs a good illustration of the movements that have 

 produced the irregular topography of this locality. A large mass of 

 rocks and earth has been detached from the steeper slopes above by 

 excessive moisture and has been precipitated into the bed of the rivulet, 

 which has thus been turned out of its course to find its way across the 

 terrace to the north into another deep gulch. 



Turning to the left I soon found myself at the top of a steep bluff 

 which overlooks the "Grotto in the glen," a hot-spring mound formed 

 by one of the highest of the living springs. In the face of the bluff I 

 came ui)on an outcrop of hard calcareous sandstone strata in which 

 there are imperfectly preserved Jurassic fossils. The exposed strata 

 have a thickness of about 40 feet. The dip is to the northeast, at an 

 angle of about 40°. Beyond this, in the cliff that borders the wagon- 

 road-pass on the north, the same rocks outcrop and have nearly the 

 same dip and strike. In the road a stratum of dark shales or slates has 

 been exposed, in which are two or three varieties of Jurassic fossils. 

 In the cliff's above there are about 500 feet of strata exposed, which in- 

 cludes yellowish quartzitic and calcareous sandstones, and toward the 

 top shales and shaly sandstones. In the harder strata a few fossils 

 were found, including species of Bhynconella, Campronectes, and a Fenti- 

 erinus. The less compact strata above contain occasional seams of 

 flinty limestone. There is much selenite and a little carbonaceous mat- 

 ter. The shales show some ripple marks. In the slide rocks there are 

 fragments of conglomerate, like that seen at the springs, which contain 



