4 



Umversitij of California Puhlications in Geology [Vol. 12 



The San Rafael Moimtains have the same northwesterly trend as 

 the Coast Ranges in general. They are extremely rugged and quite 

 irregular, since they are made up of a series of ridges usually deter- 

 mined by the strike of the strata of which they are composed. The 

 main crest rises to an elevation of 6828 feet in Big Pine Mountain and 

 6581 feet in Mission Pine (San Rafael) Mountain. Within the area 

 studied, Little Pine Mountain (4174 feet) is the highest elevation and 

 is the culminating point of a long ridge which extends northwesterly 

 from Indian Creek to Santa Cruz Creek. Loma Alta Mountain (2745 

 feet), although comparatively low, forms a prominent landmark in the 

 western border of the area. 



The Santa Ynez Mountains rise abruptly from the low, broad ocean 

 terraces on the south to a comparatively even crest line with an 

 average height of about 3500 feet. The greatest elevation is Santa 

 Ynez Peak, 4292 feet high. The range is very narrow and extends 

 from Point Arguello, just north of Point Conception, for forty miles 

 in an easterly direction to a junction with the Coast Ranges proper. 

 In its entirety, the range is very simple, being made up of a remark- 

 ably straight, single ridge, which has practically no lai-ge spurs or 

 canons. 



The drainage of this district is concentrated in the Santa Ynez 

 River which lies in the triangular-shaped lowlands between the two 

 ranges. Its course runs nearly west for its entire length at the north- 

 ern base of the Santa Ynez Mountains. The upper part of the river 

 is confined in a narrow eaiion, but to the west it gradually widens out, 

 until opposite Loma Alta j\Iountain the bed of the stream forms but 

 a small part of a widelj' terraced flood plain. In no part within the 

 area studied is the river now corrading its trench ; on the contrary it 

 appears to be engaged in the work of aggradation. The tributaries 

 entering the main stream reach back to the main divide, a distance of 

 about ten miles or more. The most important of these are Mono Creek 

 and Santa Cruz Creek. These streams cut across the strike of the 

 formations, whereas Buckhorn and Gamusa creeks follow the trend 

 of the strata. All the north side streams are low grade and in only a 

 few places are they corrading vertically. In some of the larger cafions, 

 as the ^lono, there are terraces representing former flood plains of 

 the stream. 



In marked contrast to the drainage on the north side of the river, 

 that of the Santa Ynez ^Mountains is short, high grade, and incisive. 

 Some of the streams are so steep that it is impossible to ascend the 

 canons as they are blocked by huge boulders and stepped by waterfalls. 



