1922] Hudson: Geology of the Cuyamaca Region of California 179 



Pine Hills, a summer resort situated four miles southwest of Julian, 

 and Descanso, lying several miles south of the southern limit of the 

 map, are the only other settlements of importance in the district. 



Friday Mine, which is the subject of a chapter of this report, is 

 situated four miles southeast of Julian, on the road from that town 

 to Cuyamaca Reservoir. 



The roads from Julian to Pine Hills, and to Descanso, by way of 

 Cuyamaca Reservoir, have been rebuilt since the publication of the 

 U. S. Geological Survey sheets. They do not in general follow the old 

 routes. Certain stretches of these roads are shown on the map, while 

 in those places where the writer did not take the time to obtain accu- 

 rate data a blank space has been left. The road from Pine Hills to 

 Cuyamaca Reservoir, recently built, has been plotted in. 



Belief. — The most striking topographic features of the region are 

 the Cuyamaca Mountains, whose three peaks form a ridge, rising from 

 the broad upland of the Peninsular Range. When viewed from the 

 east, this ridge is seen to rise with steep slopes to heights of from 

 5100 to 6500 feet from a region of fairly low relief which stretches 

 from the vicinity of Stonewall Peak to the north and within which 

 lies the open valley now occupied in part by Cuyamaca Reservoir. 

 On their west flanks the mountains have steeper slopes, particularly 

 South Peak, which drops off 2500 feet from the summit in a horizontal 

 distance of one and one-quarter miles. 



The main divide of the region, separating the drainage to the 

 Pacific Ocean from that to the Colorado Desert, lies in a ridge several 

 miles to the east of the Cuyamaca Mountains. This ridge has an 

 elevation of from 4500 to 5500 feet along its crest. Within the limits 

 of the map it runs from the vicinity of Julian, southeastward, passing 

 immediately east of Rattlesnake Valley. Where it bounds the region 

 of low relief north and east of Cuyamaca Reservoir this ridge rises 

 but a few hundred feet above the gently rolling country to the west, 

 while to the east is a region of deep canons and rugged peaks. To 

 the northwest, in the vicinity of Julian, the contrast between the type 

 of topography on either side of the divide is almost as striking. Here, 

 on the west side, are the open valleys of Coleman and Cedar creeks 

 and the rolling land near Julian, while on the east are the steep slopes 

 down to Banner and Chariot canons. The gently rolling summit lands 

 do not, however, all lie on the Pacific side of the divide, as the head- 

 waters of the Banner Canon stream, which runs to Salton sink, reach 

 into a part of the country of low relief near Julian. 



