GEOGRAPHY AND TOPOGRAPHY. 
17 
They are topographically and structurally young ranges, except the 
Oasmalia Hills, at the extremity of the northern line, which have the 
character of a separate and old range. 
SAN RAFAEL MOUNTAINS. 
The most prominent topographic feature is the great mass of the 
San Rafael Mountains on the northeast and east, 25 to 30 miles 
back from the ocean. The structural trend of the range is N. 50° W., 
approximately parallel with the general course of the lines of struc¬ 
ture in California, although on the whole more westerly. The range 
runs obliquely to the north-south coast line west of it, but farther 
north, where the Santa Lucia Range, its northward continuation, 
approaches the ocean the coast curves to the northwest under the 
control of the mountains. 
Although the portion of the San Rafael Range included within 
the area shown on PI. I (pocket) composes a high, rugged maze of 
ridges reaching elevations that range between 2,000 and 4,300 feet, 
this portion is in the larger aspect, but subsidary to the main moun¬ 
tain group farther east, in which altitudes approaching 9,000 feet 
are attained. The ridges are divided by steep canyons, most of which 
cut transversely across the formations regardless of the folding and 
structural lines. Rounded soil-covered slopes form a considerable 
portion of the part of this range included in the Lompoc quad¬ 
rangle, but rough, rocky slopes are likewise abundant. The range 
is traversed centrally by the well-graded canyon of Sisquoc River, 
which divides it into two mountain groups. On the south and north 
the range is bounded by wider graded valleys—those of Santa Ynez 
and Cuyama rivers. The Santa Ynez divides two distinct ranges. 
The Cuyama forms a more arbitrary division in the Coast Ranges. 
Near its mouth, at the point where it reaches the area included in 
the accompanying map, it veers to the south and cuts a narrow gorge 
across the San Rafael Mountains without regard to the structure. 
The range may be regarded as continuous across this portion of the 
river. 
Within the triangular area mapped the high ridges and mountains 
around Zaca Lake, Bone Mountain, Tepusquet Peak, and Los Coches 
Mountain are boldly defined, with steep side slopes descending into 
narrow canyons, and as a rule rounded summits. The broad ridge 
oridnatinsr north of Los Coches Mountain and extending southeast- 
ward to North Fork of Labrea Creek, where its character is tem¬ 
porarily lost until it appears again in Manzanita Mountain, is a 
striking feature with its long southwestern and abrupt northeastern 
slopes. The seaward flanks of the range terminate rather abruptly 
in the terraces bordering the Santa Maria Valley. 
