GEOLOGY. 
29 
has been considered upper Cretaceous and of one in southeastern 
Santa Barbara County that has been ascribed to the Eocene. Its 
age is therefore much in doubt. It may also include at the top part 
of the Vaqueros (lower Miocene), which overlies this doubtful ter- 
rane and of which the base has not been definitely determined. 
Structurally the strata included in this pre-Monterey group lie 
beneath the Monterey and upper Vaqueros, but though far older 
they do not bear so strongly the marks of intense folding as do the 
brittle Monterey shales. They are, however, steeply upturned, and 
the lines of folding, as in the case of the other formations, are in gen¬ 
eral in a northwest-southeast direction. 
TEJON, SESPE, AND VAQUEROS FORMATIONS, UNDIFFERENTIATED 
(eocene-miocene) . 
GENERAL STATEMENT. 
The Santa Ynez Range is mostly composed of a thick terrane of 
marine sediments equivalent to a part or all of the Tejon formation 
and the Vaqueros formation. The former is Eocene and the latter 
lower Miocene in age. This terrane comprises a continuous succes¬ 
sion of marine sediments of detrital origin, seeming to present no 
point at which an angular unconformity exists, although the line at 
the base of the coarse conglomerate containing the Vaqueros fossils 
doubtless marks a long time interval. 
In the preliminary report on the Santa Maria district 0 mention is 
made of the Sespe formation as being represented here, and a small 
area of it is shown on the map accompanying that report. The 
Sespe formation belongs to the Eocene or Oligocene and is a distinct 
formation above the Tejon and below the Vaqueros. It occurs ex¬ 
tensively in the Santa Ynez Mountains north of Santa Barbara, and 
an outcrop of blood-red sandstone in this range 3^ miles south of 
the Santa Ynez Mission was indicated on the outline map as belong¬ 
ing to the Sespe because of its lithologic resemblance to the typical 
rocks of this formation. This small area has, however, not been 
separately shown on the present map, as there is no good proof of 
its age. It is quite possible that the Sespe formation is represented 
in parts of this western portion of the range by rocks not recogniz¬ 
able on the lithologic grounds which are deemed sufficient for the 
determination of this formation in the vicinity of Santa Barbara or 
the Ojai Valley, to the east; or it may be that sedimentation was 
not operative in the western part of the range during Sespe time, and 
therefore that rocks of that age are lacking from the geologic section 
in this region. The amount of work done in the Santa Ynez Range 
does not warrant a full discussion of the structure and relations of 
a Bull. U. S. Geol. Survey No. 317, 1907, pp. 1-09. 
1784—Bull. 322—07-3 
