42 GEOLOGY. 
their banks are lined with debris, consisting of various volcanic and sedimentary rocks. 
Boulders of beautiful porphyry, filled with grass-green crystals, were found at one of these dry 
water-courses, and from their numbers I inferred that the rock was in place in the ridges. 
Other porphyritic boulders were of a delicate pink or lilac color, and some were brown and 
ack. 
Sandstone Strata, probably Tertiary.— After traversing the slope westward from the Cafiada de 
las Uvas for about eight miles, I turned southward and followed up the course of the dry bed 
of a stream among the low foot-hills of sedimentary origin, which are much cut by ravines, and 
present a barren appearance when viewed from the Tejon. Before reaching this canada I 
found a block of sandstone near the trail, from which casts and impressions of shells of the 
genera Meretrix and Stramonita were obtained. The specimens that were preserved are regarded 
as new species by Mr. Conrad, and he has named them Meretrix Tularana, Pl. III, Fig. 22; 
and Stramonita petrosa, Pl. VI, Figs. 47 and 47°. They are probably of Miocene age; and 
there is little doubt that the boulder was brought down by floods from the adjoining hills. 
After traversing the cafiada for a short distance, it was observed that the strata in some places 
were much distorted, being uplifted and set nearly on edge, and so bent that the stratification 
showed out in curved lines along the banks, with a southerly dip. These strata were much 
obscured in places by a recent drift or detritus, forming a conglomerate which rested uncon- 
formably upon their edges and filled the inequalities of surface. This is a local drift, and has 
apparently accumulated during the excavation of the valleys, the higher beds being the oldest, 
having been transported and deposited before the stream had excavated the channel to its present 
depth. ` 
As the cañada was ascended the hills became higher, and I soon found good natural sections 
of the strata with the dip towards the north. 
We left this valley, where there is running water and a line of cottonwood trees, and ascended 
the left bank, passing again towards the west. The point at which we turned is near the line 
of junction of the sedimentary formations with the granite. This may be known by the greater 
amount of the foliage on the granitic rocks and the growth of large evergreen trees, and by the 
difference in altitude and outline. A high bluff of sandstone was also near. We travelled over. 
a very rugged and irregular path, seeing high-bluffs of sandstone on the right, and on the other 
hand, or south side, thick strata of sandstone were resting at an angle of nearly fifty degrees; 
the tabular masses being broken and showing finely, with oak and pine trees, and shrubs, grow- 
ing in the fissures and between the overlapping strata. 
The path, we followed, led us for a long distance at the foot of hills composed of these hard 
sandstones, and it was evident that we followed theline of trend. The surface on each side was 
overgrown with dwarf-oaks, so thick and strong that they were impenetrable, and we were obliged 
to follow the bed of the creek, now entirely dry. The oaks were loaded with acorns of various 
sizes and forms,! and these appeared to be much sought after by bears, their paths and tracks 
being very numerous, and the only onesthat werefound. A large quantity of pebbles, composed 
of trappean and porphyritic rocks, were seen along this creek, and may have been washed out of 
the surrounding beds of sandstone and conglomerate. 
On reaching another deep valley, apparently extending towards the Tulares, we again turned 
southwards towards the high mountains, then very near us, and looking invitingly green and 
' Leaves and fruit of the most common species were collected, and have iti is considered 
Bep ; ; been submitted to Dr. Torrey. It is co! 
as Quercus agrifolia ; variety, acutidens. 
