 | The Day 4 hike had the greatest participation of any of the seven days. Assembled here, eager to be on their way, in the front row, left to right, are Franky Telles, Sue Fritsche, Vicki Pedone, and Gene Fritsche. Left to right in the second row are Stan Walker, John Alderson, Natasha Galvez, George Dunne, and Doug Yule.
 | Here is part of the group, standing on a pink sandstone exposure of the Sespe Formation looking across Hondo Canyon. The pass that we need to climb over is in the background. Photo by Vicki Pedone.
 | We made it to the pass at the top of Hondo Canyon where the trail skirts by Saddle Peak Road and are ready to continue from here on up toward Saddle Peak.
 | Here's the group hiking along the trail where it parallels Saddle Peak Road, which is down the hill below the trail.
 | After passing by Saddle Peak and starting downhill, we found a shady spot beside a large flatiron of the Lower Topanga Formation for lunch. Here's Sue, Stan, John, and Doug enjoying a well deserved break.
 | Franky, Natasha, and Vicki enjoyed their lunch also.
 | Soon after lunch we came across this idyllic scene on the north slope of Saddle Peak.
 | This is what the trail was like as we headed off the west slope of Saddle Peak down toward Piuma Road.
 | Just before the hike ended, we found this friendly rattlesnake waiting for us at the intersection of Piuma Road with Malibu Canyon Road.
 | For the fourth time we made it successfully to our van parked at the end of the trail. Some were a little sore, but all in all it was a very pleasant and enjoyable day.
 | Flowers were abundant along the trail, many at the peak of their blooming period. This picture and the next five show some of the prettiest and most prolific that we saw. Chaparral bushes like this one were ablaze with white to blue blossoms from the beginning of the hike to the end. The genus name of this bush is Ceanothus.
 | These yellow flowers grew on tall bushes that were also found all along the day's hike, from beginning to end.
 | Lupine were plentiful all along the trail. The scientific name for this purple-flowered plant is Lupinus nanus.
 | These beautiful yellow and orange flowers grow low to the ground and are called Treasure Flowers. They belong to the genus Gazania. We found them in the vicinity of Saddle Peak.
 | These clumps of small yellow flowers were spotted occasionally along the trail.
 | These California Poppies, the California State flower, we found at the end of the hike along Piuma Road. The scientific name is Eschscholzia californica.
 | Three different rock formations were seen during the Day 4 hike. The oldest was a pink-colored sedimentary rock unit called the Sespe Formation. It originated as river deposits beginning about 40,000,000 years ago and is seen in the bottom half of this picture taken of the western slope of Hondo Canyon. On top of the Sespe Formation is the brown to gray sedimentary rock unit seen in the top half of the picture. It is called the Lower Topanga Formation and was deposited in shallow ocean water beginning about 25,000,000 years ago.
 | This exposure of the Sespe Formation near Saddle Peak shows two sequences of red mudstone deposited during floods on river floodplains outside of the main river channel bounding a layer of brown, cross-bedded sandstone deposited as sand waves within a river channel.
 | These large impressions of scallop shells found in the Lower Topanga Formation prove that the rock unit was deposited in the ocean. They are about 6 inches in diameter and their scientific name is Vertipecten bowersi.
 | These two moderate-sized clams were found eroded out of siltstone beds in the Lower Topanga Formation. Their scientific name is Tellina oldroydi. They did not come out of the sandstone bed on which they are resting for picture taking purposes. Note that the two shells of the clams are still articulated (hinge together as in life). This indicates that they lived in a relatively quiet environment and were not washed around by strong currents after they died. Such an environment would have existed during deposition of the siltstone in which they were found.
 | The shallow depressions in this Lower Topanga sandstone mark where rounded mudstone fragments have eroded out of the sandstone. These mudstone fragments are called rip-up clasts. They indicate a strong current on the bottom of the ocean that was eroding a mudstone bed upcurrent from the site of deposition. The broken mudstone fragments were rounded as they were transported to this location and deposited with the sand grains that make up the remainder of the sandstone bed.
 | The pattern shown on this sandstone bed is called a sole mark because it was created on the bottom of the sandstone bed. The sandstone bed, therefore, is presently oriented upside down. A rapid, sand-laden current scoured out the pattern on a mudstone bed that was previously underlying the sandstone. As the current waned, the sand grains settled and filled in the pattern that had been created in the mudstone. Then, eventually, the sand grains hardened into rock. The current that created this structure was flowing from upper left to lower right.
 | The wavy pattern seen in the thin laminations in this sandstone bed are referred to as climbing-ripple laminations. The pattern was created when sand ripples migrated across the bottom of the ocean under the influence of a moderate current. Fine sand grains accumulated on the tops of the ripples while they were migrating. The current that created these ripples was moving from right to left in this picture.
 | Above the Topanga Formation, a volcanic unit of lava flows and volcanic mudflows accumulated. This rock unit is called the Conejo Volcanics and has been dated at about 17,000,000 years old. This unit is the same age and of the same origin as the lava flow rocks called the Middle Topanga Formation that were seen in Griffith Park. Shown here is a lava flow unit of basaltic composition that consists of broken fragments of lava pillows mixed with lava that has since cooled into rock. Lava pillows are created when lava is extruded from an underwater flow in the shape of blobs, or pillows. These fine-grained, pillow-shaped, obsidian-like blobs cool quickly, shatter in the cold water, break up into smaller pieces, and then become engulfed in the advancing lava flow.
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