 | (Map site 1.) The base of the resistant sandstone bed is the contact between an underlying Conejo Volcanics (17 Ma) lava flow breccia and an overlying lens of Middle Topanga Formation sandstone and shale (see next photo).
 | (Map site 2.) Interbedded sandstone and shale graded turbidite deposits of the lower Miocene Middle Topanga Formation.
 | (Map site 3.) Low areas in the foreground are underlain by the nonresistant Conejo Volcanics, whereas the hills in the background are underlain by the very resistant Lower Topanga Formation. The contact at the base of the hill between the two is the Redrock fault (see next photo).
 | (Map site 4.) The Redrock fault traverses nearly parallel to the plane of the photo between the brown, bare hill of Conejo Volcanics and the higher, vegetated slopes of the Lower Topanga Formation. Note that the bedding in the Lower Topanga Formation is truncated almost at a right angle by the fault.
 | (Map site 5.) Roadcut exposure of a basaltic lava flow breccia in the 17-million-year-old Conejo Volcanics. These lava flows flowed down the slopes of a very large, extinct volcano whose center and highest point was farther west in the vicinity of what is today Conejo Mountain.
 | (Map site 6.) Closeup of the flow breccia shown in the previous photo. This rock forms as molten lava flows across the surface picking up already hardened pieces of weathered lava from earlier flows and mixing them into the new flow.
 | (Map site 7.) Thin lenses of light gray, fossiliferous sandstone interbedded between lava flows of the Conejo Volcanics.
 | (Map site 8.) Closeup of the lower of the fossil beds shown in the previous photo. Disarticulated fossil oyster shells that were likely picked up by storm waves near shore and washed a little way offshore and deposited with sand in a thin lens on top of a shallow-water lava flow.
 | (Map site 9.) This basalt lava flow in the lower Miocene Conejo Volcanics contains holes that formed in the lava as gas bubbles.
 | (Map site 10.) Molten lava contains dissolved gas. When the lava rises from underground to the surface, pressure is released (as in uncapping a soda pop bottle) and gas bubbles form in the lava. The bubble holes are called vesicles and the rock is said to be vesicular.
 | (Map site 11.) This exposure of a basaltic Conejo lava flow shows vesicles that have been filled with mineral deposits. Groundwater saturated with minerals that passes through the rock after the lava has cooled deposits the minerals in the vesicles or bubble holes.
 | (Map site 12.) Closeup of the mineral-filled vesicles shown in the previous photo. These filled vesicles are called amygdules and those shown here are filled with the mineral calcite.
 | (Map site 13.) The middle Miocene Upper Topanga Formation is a nonresistant unit and good outcrops are rare. It was deposited between 17 and 13 million years ago. Shown here in a small canyon east of Liberty Canyon are a few sandstone exposures of the formation.
 | (Map site 14.) This roadcut on Chesebro Road is in the middle Miocene Upper Topanga Formation. Although the roadcut is relatively new, it is already deeply weathered. It is covered with straw to promote vegetation growth and to keep it from eroding away.
 | (Map site 15.) A small exposure of the middle Miocene Upper Topanga Formation found in the roadcut shown in the previous photo. It is a fine-grained, thin-bedded sandstone and shale formation.
 | (Map site 16.) Outcrop found in a stream bed of the upper Miocene Monterey Formation that was deposited between 12 and 5 million years ago. It is a siliceous shale formation that in places has been completely recrystallized into chert.
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