JUNCTION PEAK. 281 



an angle of 45°. In the deeper- cut ravines of the Tertiaries, to the south 

 and west of the ridge, toward Lily's Park, are found several exposures of 

 sandstones, evidently belonging to members of the Cretaceous group, 

 which form part of the Junction Peak fold. The surface of the south- 

 ern portion of the Junction Peak Eidge shows only the beds of coarse 

 gray, and compact whitish limestones of the Upper Coal-Measurcs. Its 

 highest peak is capped by a flat mass of these limestones, dipping slightly 

 west, while in the deeper ravines near the summit are found exposed the 

 brownish underlying sandstones- of the Weber Quartzite, in general almost 

 horizontal, or with a dip of a few degrees to the westward. To the north 

 of the peak, the same rocks are found exposed, the strata showing signs of 

 dislocation and faulting. At the northern point, the limestones dip 40° 

 northward, flattening out to 25° on the extreme foot-hills. 



The upturned edges of the higher members of this fold arc mostly cov- 

 ered by the v/hite Tertiaries, or obscured by drift material. On the western 

 side of the peak, however, near the Little Snake River, at the northern part of 

 Lily's Park, where the stream cuts deeply into the Tertiaries, good exposures 

 are found of these beds, showing the Triassic sandstones, the clays and lime- 

 stones of the Jurassic, and some sandstones and clays of the lower members 

 of the Cretaceous. In the section thus exposed, the beds strike north 45° 

 west, and dip 45° to the southwest. Looking at these outcrops from the 

 benches above the canon of the Little Snake River, in the direction of the 

 strike, one would at first be led to conclude that there was a decided un- 

 conformity between these beds, and those which form the summit of Junc- 

 tion Peak, where the red quartzites overlain by drab limestones are seen 

 dip to only 7° westward, while the lowest exposures of the Triassic have 

 a dip of 45°, as already stated. The sharp flexure and break on the edges 

 of the central fold easily account for this apparent unconformity; and 

 where the Tertiaries, which cover the benches of Lily's Canon, have been 

 denuded, the Upper Coal-Measure limestones may be found confoimable 

 with the Triassic sandstones. No fossils were found in the limestones of 

 Junction Peak; but those on East Mountain, directly to the west of it, the 

 lithological character of whose beds, and their relative position establish 

 their identity, abound in characteristic Carboniferous fossils, among which 



