SANTA CLARA VALLEY: VAQUEROS FORMATION. 13 
IN TRIBUTARY ENTERING LITTLE SESPE CREEK AT FOOT-OF-THE-HILL WELLS. 
Balanus concavus Bronn. (PI. XXXII, figs. 5, 5a). 
Pecten sespeensis var. hydei Arnold (PI. XXXI, fig. 2). 
Placunanomia sp. 
Scutella fairbanksi Merriam (PI. XXIX, fig. 3; PI. XXX, fig. 3). 
LITTLE SESPE CREEK, BELOW FOOT-O F-THE-HILL WELLS. 
Balanus concavus Bronn. (PI. XXXII, figs. 5, 5a). 
Pecten sespeensis Arnold (type locality) (PI. XXXIII, figs. 1, la, 2). 
Trophon n. sp. (large). 
Turritella ineziana Conrad var. sespeensis Arnold (PI. XLI, fig. 6). 
The limestones bearing these fossils are conspicuous in their per¬ 
sistency. One or another appears at intervals for several miles 
along the Tar Creek trail; again on upper Fourfork Creek, half a 
mile west of the upper wells; on Little Sespe Creek below the Foot- 
of-the-Hill wells; and in a tributary that enters Little Sespe Creek in 
the vicinity of the Foot-of-the-Hill wells. Besides the foregoing 
fossils, both shale and limestone, from base to summit of the forma¬ 
tion, afford an abundance of foraminifera and fish integuments. 
The Vaqueros thus exhibits a degree of lithologic and paleontologic 
resemblance to the shale of the overlying Modelo formation. The 
stratigraphic position and unique fauna, however, determine the age 
of these beds, and the sharp line between them and the Modelo sand¬ 
stones above indicates that the division between the two formations 
should be located at that plane. 
About 30 feet below the contact of the gray and overlying maroon 
shale is a very persistent band of gray sandstone from 10 to 40 feet 
thick, the outcrop of which may be readily seen about the extensive 
amphitheater drained by Tar Creek. 
The upper series, of calcareous and siliceous shales, is strikingly 
similar in appearance to the Modelo of adjacent localities; moreover, 
they abound in foraminiferal forms. Were the Modelo sandstone to 
disappear and the shales of the Vaqueros and upper Modelo to be 
brought in contact it would be impossible to distinguish a break of 
importance in the entire succession. It is suspected, indeed, that 
this has happened in the western face of Oat Mountain and in the 
ridge running southward, although with a thinning of the series as a 
whole. 
VAQUEROS BEDS IN THE OJAI VALLEY. 
The Vaqueros formation in the Ojai Valley is composed of rust- 
colored conglomerate, sandstone, and shale, together with inter- 
laminated limestone. The conglomerates carry pebbles up to 2 
inches in diameter of black chert, white quartzite, gray granite, and 
purple, green, and maroon eruptives. In places, also, there are 
pebbles that possibly may have been derived from some outcrop of 
