GEOLOGY. 
I 
31 
shale is mentioned by II. W. Fairbanks in the two quotations given 
under the heading 11 Previous knowledge of the geology, ” pages 12-13, 
and this author discusses them further in his paper there cited. 
STRUCTURE AND THICKNESS. 
Like all the Tertiary and pre-Tertiary formations of this region 
the deposits under discussion have been subjected to folding that 
has left none of them in an undisturbed attitude. But as they con¬ 
sist in large part of soft sandstone and conglomerate with inter- 
bedded layers of sandstone and clayey shale, they have not been so 
violently fractured and disturbed as much of the brittle shale of the 
lower portion of the Monterey (middle Miocene). The high ridge of 
the Santa Ynez Mountains from Point Conception eastward is formed 
by a great monocline in the sandstone of this terrane, dipping toward 
the sea on the south at an angle of about 30°. North of this ridge 
occurs a longitudinal depression in the range in which the folds of 
the beds are rather low; and still farther north, bordering the Santa 
Ynez Valley, these rocks are considerably disturbed, dipping in 
various directions and at all angles between 15° and the vertical. 
The general inclination of the beds on the north side, however, is 
northward, the structure of this part of the range, broadly viewed, 
being anticlinal. In the San Rafael Mountains the Vaqueros strata 
are steeply folded along northwest-southeast lines, in conformity 
with the overlying Monterey. A marked example of the way in 
which the soft, coarse conglomerate has been left little affected 
occurs in Buckhorn Canyon, where thick beds of this rock, probably 
the basal part of the Vaqueros, lie almost horizontal. 
The Tejon-Sespe-Vaqueros rocks have a thickness of at least 5,000 
feet in the Santa Ynez Mountains, and further work will probably 
allow these figures to be considerably increased. 
AGE AND FOSSILS. 
At least two distinct faunas are found in the Tejon-Sespe-Va- 
queros strata. The lower is characteristically Eocene, and similar 
to that of the Tejon formation of the type locality; the upper con¬ 
tains many of the species found at the type locality of the Vaqueros 
formation, which is the standard lower Miocene of the central Cali¬ 
fornia province. So far as is definitely known no species bridges 
the gap between these two faunas, either here or elsewhere in Cali¬ 
fornia, although the beds containing the two are apparently con¬ 
formable not only in the Santa Ynez Range but also locally as far 
north as Martinez, east of San Francisco Bay. 
