 | (Map site 1.) Outcrops of the soft, nonresistant Miocene rocks in Cheeseboro and Las Virgenes Canyons are rare. This is one of the few exposures of the upper Miocene Monterey Formation that we found.
 | (Map site 2.) Recent landslide on the east side of Las Virgenes Canyon. The failure scarp is the cliff in front of the ridge in the center skyline. The mound in the left center of the photo is the accumulated pile of debris at the base of the landslide. This slide occurred in 1981 and is younger and larger than the landslide shown on the Dibblee geologic map.
 | (Map site 3.) Conglomerate deposit in the middle Miocene Upper Topanga Formation. Conglomerate is not common in this formation south of Highway 101 in the Santa Monica Mountains, but it is very common between here and the western end of the San Fernando Valley.
 | (Map site 4.) Although thick, resistant sandstone beds are the hallmark of the Upper Cretaceous Chatsworth Formation, there are many sections, usually hidden under vegetation, that consist predominantly of shale and thin-bedded sandstone like this roadcut exposure.
 | (Map site 5.) A typical thin sandstone bed in the Upper Cretaceous Chatsworth Formation. It was deposited by a tubidity current on the middle slopes of a large submarine fan. The base of the sandstone layer (at the pen point) starts with parallel-laminated sand deposited by a rapidly flowing current entraining medium-size sand grains. As the current slows, the medium sand grains are deposited on the bottom and the fine-sand grains remaining in the current are formed into ripples on the bottom, as seen in the upper part of the sand layer. As the current continues to slow, the fine sand is deposited in the ripple layers leaving only the darker silt and clay particles to fall to the bottom as the current comes to a stop. This sand bed was deposited as a single event over a period of just a few hours.
 | (Map site 6.) This conglomerate layer of pebbles and cobbles in the Upper Cretaceous Chatsworth Formation represents deposition in a submarine channel on the middle slope of the submarine fan. This is the same submarine fan whose upper fan delta slopes were observed in the Tuna Canyon Formation in the Santa Monica Mountains on May 24 and 26.
 | (Map site 7.) Thick deposits of the Paleocene Simi Conglomerate. This rock unit is not very resistant and is commonly recognized by the abundant cobbles and boulders lying around on the surface of the ground.
 | (Map site 8.) Thick boulder conglomerate in the Paleocene Santa Susana Formation. Conglomerate in this rock unit is not as common as sandstone and shale, but this exposure is very impressive.
 | (Map site 9.) Looking west at exposures of the Paleocene Santa Susana Formation. Most of the rock layers in the center of the photo are sandstone, but in younger layers at the top of the ridge on the right, the sandstone is replaced by brown shale.
 | (Map site 10.) A resistant fossil bed (between the ends of the pen) in the Paleocene Santa Susana Formation. The abundance of fossils in this layer, compared with the relative lack of fossils in the surrounding layers, indicates accumulation as a storm deposit. Living shells in shallow ocean water were picked up by strong storm waves and washed offshore where they were piled up and buried by sand. If any were still alive after downslope transport, they were unable to escape their tomb.
 | (Map site 11.) Closeup of the fossils in the fossil bed shown in photo 10. Large clam shells and the turret snail Turritella make up the bulk of those seen. After burial, some of the calcium carbonate in the shells dissolves and moves with the ground water into the surrounding sand where it is precipitated to form a hard, concrete-like tomb for the shells.
 | (Map site 12.) Typical exposure of the Upper Cretaceous Chatsworth Formation. The hogback ridges consist of thick sandstone beds deposited by large turbidity currents on the middle slopes of a submarine fan. In between the ridges are nonresistant shaley layers.
 | (Map site 13.) Flame structures in the Upper Cretaceous Chatsworth Formation. Passage of turbulent flow in the turbidity current that deposited the sand layer in the top of the photo lifted up the underlying, water-laden silt and clay layers into pointed structures referred to as flames.
 | (Map site 14.) Looking at the bottom side of a sand layer in the Upper Cretaceous Chatsworth Formation that was deposited by a turbidity current. As the current moved down the slope, it carried with it a pebble that was heavy enough to be dragged on the bottom, leaving a groove in the muddy bottom. As the current slowed and stopped, the groove was filled with sand that settled to the bottom. On the layer below is a smaller infilled groove made by an animal like a worm or snail that had been burrowing in the muddy bottom.
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