Geology:   Geologic Map of Newhall Pass


Saugus Formation, undivided

Age: Late Pliocene – Early Pleistocene (3.6 – 1.806 Ma)

Stratigraphic name: Saugus Formation

Description: Slightly consolidated, poorly sorted, coarse-grained, cross-bedded sandstone and pebble conglomerate; chiefly nonmarine, but includes a few interbeds of marine and brackish water depositional environm >>>

Reference: Alvarez, R.M. and K.R. Bovard, 2005, Preliminary Geologic Map of the Los Angeles 30′ x 60′ Quadrangle, Southern California: U.S. Geological Survey Open-File Report 2005-1019. 2668588.

Saugus Formation

Age: Piacenzian – Pleistocene – (2.841 – 0.8705 Ma)

Thickness: 0 – 1388m

Unit ID: 6343



Looking south at the corner of Sierra Highway and Lancaster Blvd. in Lancaster in 1913
The first road to use the general alignment of modern Route 14 was called the El Camino Sierra, or Sierra Highway, which extended from Los Angeles to Lake Tahoe. A dirt road was completed in the 1910s from what had been a pack trail. The Los Angeles Times declared El Camino Sierra complete in 1931, when the portion from Mojave to the Owens Valley, along modern US 395, was paved.[13] During the late 19th century, the corridor of modern Route 14 was also in use by the Southern Pacific Railroad for two lines. The first is a line to connect Los Angeles with the Central Valley, via Tehachapi Pass. While significantly longer than the more direct Ridge Route (east of modern Interstate 5), Tehachapi Pass is lower than Tejon Pass along the Ridge Route, with a longer, less steep grade on the descent into the Central Valley.[10] This rail line remains the primary rail line to connect southern and northern California in use today, now owned and operated by the Union Pacific Railroad.[14] The second resulted when the Southern Pacific acquired the un-finished Carson and Colorado Railroad in 1900.[15] The Southern Pacific built a standard gauge connector to the narrow gauge Carson and Colorado line from their main at Mojave. Although plans were to eventually convert this acquired line to standard gauge, most of the line was abandoned before the conversion was complete. However, the southern portion of this line is still active and used for connections to the Trona Railway.[10][16] The Midland Trail was one of the first organized coast-to-coast trails in the United States.[17] In the trail’s infancy, its routing changed numerous times. By 1925, the Midland Trail was established along what is modern State Route 168, joining El Camino Sierra in Big Pine.[18] Other named trails that would eventually follow this route included the Theodore Roosevelt highway,[18] and Grand Army of the Republic Highway.[19] Parts of modern Route 14 continue to be signed with these names,[6] and north of Los Angeles County is still officially designated “El Camino Sierra / Midland Trail” as well as the aforementioned “Aerospace Highway”.[6]

U.S. Route 6[edit]

U.S. Route 6 was extended from Greeley, Colorado to Long Beach, California on June 21, 1937.[19] Most of this extension used the Midland Trail, although the route entered California from Nevada slightly north of the previous route of the Midland Trail, instead passing through Bishop. While being designated US 6, parts of modern Route 14 began to be upgraded to freeway standards. As part of the 1964 state highway renumbering, US 6 was truncated at Bishop. The portion of US 6 from Inyokern to Los Angeles was designated State Route 14. Previously the Route 14 designation was used for Artesia Boulevard and Lincoln Avenue, in the Los Angeles area, a portion of modern State Route 91.[20] Between 1963 and 1975 significant portions of US 6/SR 14 were moved to a freeway alignment. The former routing south of Mojave (and the current routing to the north) is still known as Sierra Highway. The first freeway section, from just east of Solemint Junction to Red Rover Mine Road, was completed in 1963. Further portions in the intercanyon areas of Acton to Soledad Pass were completed by 1965. By 1966 the freeway was complete as far north as Avenue P-8 in Palmdale. The freeway was completed to Mojave by 1972.[21] by Michael Ballard   Geology

The Santa Clarita Valley has a very diverse geologic history and makeup. Fossils abound here, as well as gold, howlite, and oil. During the mid to late 1800’s, there was gold fever here. Acton, Soledad City (later Ravenna), and Placerita Canyon were the hubs of the mining activities. Only Acton remains as a gold producing area today. There was an actual gold rush in Placerita Canyon starting in 1842 – six years before the discovery at Sutter’s Mill. Oil was also discovered here during the same time period. During the 1870’s and 1880’s, oil was king here. Mentryville, a town about 3 miles west of Newhall, was an oil boom town. It was founded in the mid 1870’s. Oil is still being pumped from the ground around here, only now the main operations are in Placerita Canyon and near Castaic. Most of the valley is composed of sedimentary rocks ranging from 30 million years old to about 1.8 million years old. The valley floor is composed of alluvium from rivers and streams. Some of the oldest rocks in Southern California are located just five miles from here. They are a part of the San Gabriel Basement Complex and have been dated to about 1.7 billion years old. However, the last five million years here are the ones I will concentrate on, as this is when this valley began to take its present form. During the Pliocene Epoch, much of this area was covered by the Pacific Ocean. It was shallow and was teeming with life. The life that once was here has left numerous fossils. These fossils include gastropods, clams, oysters, plants, fish, whales, and even dolphins. The waters that were here were warm but not warm enough to support more tropical forms of life such as coral. This whole area underwent drastic changes starting at around 1.5-2 million years ago. All the way up the coast, mountains were forming. These mountains exist today as the Coast Ranges. The sea receded and the land rose from below sea level to over 5000 feet in some places. This valley also took on a very different appearance. During the early Pleistocene, the Santa Clarita Valley was a much broader and shallower valley. The uplift that help to create the Coast Ranges also caused the dissection of the older valley floor creating the many stream terraces visible today along the sides of the canyons. Not all the mountains were formed around this time, however. The San Gabriel Mountains started forming  about 12 million years earlier during the Miocene Epoch. Most of their uplift has occurred only in the last three million years. One of southern California’s major fault lines can be traced right through here. Its name is the San Gabriel Fault and is an inactive branch of the San Andreas Fault system. Tracing its path is very easy. You can follow it from Pacoima Canyon, Bear Divide, Placerita Canyon and just west of Violin Summit on I-5. The photo below shows the fault as it runs through Pacoima Canyon.
Along Little Tujunga Canyon Road. The San Gabriel Fault is visible where the light rock meets the dark rock in the center of the photo.
Along Little Tujunga Canyon Road. The San Gabriel Fault is visible where the light rock meets the dark rock in the center of the photo.
In the Santa Clarita Valley, it runs through Placerita Canyon, through the summit on Sierra Highway and SR-14 near Golden Valley Road, along Magic Mountain Parkway from near Bouquet Junction, through the industrial center, and then running sub parallel to I-5 from Castaic north. The San Andreas Fault is another major fault that runs in the area. It, however, is about 15 miles north of here. Even so, it can still have a devastating impact if a major earthquake was to occur on it. The fault, in this area, runs through San Bernardino, through Cajon Pass, Wrightwood, Devils Punchbowl, Palmdale, Leona Valley, under Frazier Park, and along the western edge of the Great Central Valley. The last time that segment broke was in 1857. It ruptured from Parkfield all the way to San Bernardino – over 200 miles! Fault slippage is estimated to be at about 30 feet.
The following sections will give more detailed descriptions of each areas geology. Please feel free to ask any questions if you cannot find what you are looking for. scvgeo
Geological map of the Santa Clarita area. Portion of the Los Angeles Sheet - 1969 - California Geological Survey
Geological map of the Santa Clarita area. Portion of the Los Angeles Sheet – 1969 – California Geological Survey