CANADA DE LAS UVAS—GRANITIC ROCKS. 209 
not as well exposed as in the ravines of the Tejon Pass. The whole width of the granitic expo- 
sure, by direct section across the strike of the planes of structure, is less than seven miles, but, 
including a second ridge, the point of which is skirted, itis about ten. The formations bounding 
the Pass for the remaining distance are Tertiary sandstones and accumulations of drift, with 
occasional outcrops of intrusive rocks. 
The geological section of the Cañada, Section 7, Sheet IV, is constructed like that of the 
Tejon Pass, although on a different scale. It is intended to exhibit, as nearly as was ascer- 
tained, the structure or lamination of the rocks as they are exposed along the sides of the 
Cañada. As the prevailing trend of the planes of structure is east and west, the observations 
are referred to a straight line running north and south, so that the relative positions of the 
different parts of the rocks might be exhibited. Only that part of the section included between 
stations 1 and 40 are referred to this line. The portion showing the Tulare slope is along a 
line connecting station 1 with Kern Lake. The remainder of the section, from 40 to 74, is 
along the line of the trail, (east and west, see map,) and it is parallel with the prevailing trend 
of the formations. It is given merely to show the average elevation of that part of the Basin, 
and to indicate the character of the hills bounding the trail. 
The first four miles of the pass is a narrow gorge, averaging less than one-quarter of a mile 
in width; it is in this portion that the principal exposures of the rocks occur. These rocks 
have a general similarity to those of the western slope of the Tejon, being generally hard and 
compact, although highly structural or laminated. Mica, however, appears to occur in greater 
abundance, and a part of the rock is unlike any observed in the section at the Tejon. That 
portion of the rock near the entrance from the Tulare slope is without hornblende, which 
appears to be entirely replaced by mica, in crystals about one-quarter of an inch broad. This 
mica is also disposed in narrow veins, traversing the rock, and looking, on the exposed edges, 
like black hornblende. 
About two miles from the entrance the rock is highly laminated and less dense, and might be 
called a coarse mica-slate. Several of the specimens were very dark colored, and appeared to be 
imbued with plumbago. Half a mile beyond, the rock is more compact and like ordinary 
granite, and contains a considerable portion of white, silvery mica. Garnets were also observed. 
Beyond this, and nearly three miles from the entrance, the rock becomes more laminated and 
gneissoidal, and is sueceeded beyond by more compact rock. This contains hornblende, and is 
thus syenitic, but is highly laminated or structural, and is traversed by quartz veins, About 
four miles from the entrance the rock becomes like the gray granite of the Tejon Pass and 
Tejon ravine, and contains similar lenticular aggregations of mica and hornblende. Here the 
valley of the Pass becomes more open, and the rocks are not favorably exposed for observation. 
The camp was located in this part of the valley in a grove of oak trees. Beyond it, and 
between stations 3 and 6, outcrops of white crystalline limestone occur, and trend obliquely 
across the valley, or nearly east and west. Nearly opposite station 15, at the end of the ridges 
where the valley opens towards the southwest, limestone again appears in several outcrops, 
apparently parallel with those first observed. The intermediate space is occupied by granitic 
or metamorphic rocks, but they are much hid, and indeed almost entirely covered, by a thick 
deposit of drift or Tertiary strata. The ridges terminate at this point, and are separated from 
those beyond by a narrow valley, and the small lake or pond called Casteca Lake, which, when 
dry, is white with salt left by the evaporation. 
The granitic ridge which bounds this lake on the south is so much covered with.soil and 
27 F 
