and overlying the Vaqueros Formation. At the ground surface, the contact with the Vaqueros is obvious along the south slope of the mountains, for it is almost always defined by the line dividing the rounded, grassy foothills from the more rugged, chaparral-covered sandstones upslope.

Thickness of the unit at the surface ranges from about 1400 to 1700 feet south of the mountain crest, averaging 1600 feet. It is less thick north of the mountains, attaining a maximum thickness of around 1000