SHEEP EIDGE. 1G9 



SOUTHERN DIVISION. 



The remaining portion of the eastern slopes of the range included in 

 the map, south of Horseshoe gulch, presents but few good exposures as com- 

 pared with the region already described. Its altitude is generally lower 

 and the surface is covered with forest growth and very considerable accu- 

 mulations of Quaternary gravels; still, the general outline of its structure 

 is not difficult to seize. 



sheep Ridge From Sheep Mountain to Round Hill the crest of this 

 ridge becomes gradually lower, and beyond the latter it disappears under 

 the plain. Immediately south of the summit of Sheep Mountain is a slight 

 depression, from which the White Porphyry has been eroded off, exposing 

 the underlying Blue Limestone. Again, at the first prominent saddle in the 

 ridge, Blue Limestone forms the crest and "the eastern slopes, and beyond 

 this to Warm Spring pass White Limestone outcrops along the crest, show- 

 ing that the topographical slope descends more rapidly than the geological. 

 At Warm Spring pass fragments of Red-cast beds on the crest indicate that 

 the whole thickness of the Silurian probably comes to the surface here, 

 although no actual oittcrops of Cambrian beds could be detected. The 

 steep western slopes of the ridge toward Sheep Creek, in this extent, are 

 formed of. easterly-dipping Weber Grits, and are therefore on the western 

 side of the London fault. On the eastern slope the White Porphyry sheet 

 appears to be continuous above the Blue Limestone, and at the Warm 

 Spring pass has thinned out to 20 feet. The so-called Warm Spring fur- 

 nishes a considerable flow of water, of a temperature of about 60, from the 

 upturned strata near the base of the Blue Limestone. South of Warm 

 Spring pass, judging from the meager data afforded by outcrops, the geo- 

 logical slope becomes greater than the topographical. The Blue Limestone 

 forms a cliff half way up the slope on the south side of the pass, and beyond 

 this the only rocks found on the surface are those belonging to the Weber 

 Grits ; these on Round Hill have an anticlinal structure, dipping to the 

 east, south, and west, although along its extreme western face an eastern 

 dip is again found, which is the commencement of the slope of the beds 

 upwards toward the crest of the main range. The explanation of the 

 structure of this portion of the hill is that the fault movement has died out 

 and only the fold remains. 



