Streambed Alluvium
High porosity in the alluvial gravels and sands allows good drainage for water that runs year-round. Thick brush, poison oak, willows, and oaks thrive in the alluvium of the streambeds.

Fanglomerate
Oak savannah is the typical cover for the broad, high sweeps of the Fanglomerate. This area contains sandy ground filled with boulders, and grassland dotted with occasional oaks.

Rincon Shale
Grasslands in the lower elevations are underlain by a dark, thick clay soil that has weathered from the Rincon Shale. Grasses can tolerate this area where the clay soil is characterized by low porosity, swelling when wet, and shrinkage cracks when dry.

Vaqueros Sandstone
Scrubby brush, yucca and some oak grow in the steeper slopes underlain by the Vaqueros Sandstone. Between rocky outcrops, the soil is tan and sandy with good drainage.

Sespe Redbeds
Heavy brush and chaparral grow in the silty soils of the Sespe redbeds. Where there is more sand present, some grasses grow as well. Local avocado farmers take advantage of the Sespe soils for their orchards. These can be seen in abundance along Casitas Pass Road below Carpinteria, and to a lesser extent in some of the Sespe hills north of the Foothill property.