All posts by Michael F Ballard

Michael F Ballard is the author and administrator of the Southern California Regional Rocks and Roads website, https://socalregion.com, since 1995. I have been studying the geology and highway history throughout southern California for most of my life. I am also the President of the Ridge Route Preservation Organization. Founder of the Historic Highway 99 Association of California, https://historic99.org .

What is a “C-Monument”?

Roadways and their rights-of-way are marked in various ways. Originally, roadway rights-of-way were poorly marked, and as a result, changed quite a bit. These changes made travel sometimes rather confusing as the roadway path may have changed before the map the traveler used changed. This sort of problem also cost the State quite a bit of money as they had to not only correct the problem, but also deal with the potential land costs of a new alignment.

Starting in 1914, the California Highway Commission came up with a plan to mark the right-of-way in a more permanent manner. Their solution – a “C-Monument”. While not the official name, which is simply “survey monument” or “right of way monument”, it aptly describes the marker. These monuments would be placed at the edge of the right-of-way at intervals along tangents (straightaways) and at curve points (BC and EC or Beginning of Curve and End of Curve). Optimally, these monuments would project about one foot above the ground with the C facing the roadway. The C stood for California, as in the California Highway Commission. At the top of the monument, a copper plug was placed to help guide surveyors. Per the January 1949 Division of Highways Standard Specifications manual, “Monuments shall be set firmly and vertically in the ground to a depth of at least three feet.”

Old C-Monument State Highway Right Of Way marker from 1930.
C-Monument along a 1930’s alignment of US 6 in Red Rock Canyon.

The C-monument was actively placed and used for many years, though when it finally was out of use seemed to vary between districts. In San Diego County in District 11, for example, they were used along freeways constructed in the mid to late 1950’s. Los Angeles County, within District 7, seemed to stop using them sometime in the late 1930’s. Today, the monuments that remain are still valid survey monuments. While not placed anymore, Caltrans, as well as local agencies, still use them. As such, please do not disturb or collect them if they are still in place.  Finding them along a roadway also doesn’t automatically make it an old State Highway. Some counties also used these monuments as they were a part of the standard plans for any project that involved state or federal dollars, such as Del Dios Highway between Lake Hodges and Rancho Santa Fe in San Diego County.

Finding these monuments is actually quite simple. Typically, roadway rights-of-way ranged anywhere from 100′ to more than 300′. Find a curve in the roadway you are looking at and look for one on either side of the roadway about 50 to 150′ away from the centerline of the roadway. In mountainous areas, the uphill one tends to be easier to spot than the downhill side. Fence lines, power lines, and other similar features can be used to indicate the right-of-way edge. As they can still be used today as survey monuments, some are marked with paddles or other objects to make a surveyors job easier when locating them. Placer County uses a white “R/W” paddle. Caltrans District 9, at least in Inyo County, uses orange poles as location markers.

Related Links:

Seeking Old Highways – A Guide

Image of the Week – 8/27/2017

Looking toward Timber Mountain with Mt San Antonio and Cattle Canyon to the left.

Trip to the San Gabriels

From Thursday to Saturday this week, I shall be touring the San Gabriel Mountains on my motorcycle. My plan, thus far, is to check out the roads around Lytle Creek, San Gabriel Canyon, Glendora Ridge, San Antonio Canyon, Angeles Crest Highway, Angeles Forest Highway, San Dimas Canyon, and much more. The trip should be a lot of fun, even though just the paved roads will be covered. There is always much to explore in Southern California.

Upcoming Highway Tours

While no dates are set as yet. I am planning to do two more tours in the next couple of months. The first tour will be in early October and will cover US 80 from San Diego to Ocotillo, unless temperatures are predicted above 90 F. After that, the next tour, sometime in early November, will cover US 99 from Newhall Pass to Grapevine. The accessible portion of the Ridge Route will also be covered, depending on the weather. Dates will be set in the next couple of weeks.

Cajon Pass Tour – August 12, 2017 – Review

Former Douglas gas station in Devore, CA

The tour began at Devore, CA at about 8:30 am after meeting a friend, who ended up being the only person to show. After a quick briefing on what we were to see, we headed south to Verdemont, where we inspected a freeway overpass that had remained mostly intact from its original 1950’s construction. The bridge rail and approach guard rail was original and relatively untouched. From there, we headed back to Cajon Blvd and viewed the old concrete alignment at Verdemont.

Little League Drive OC over I-215

After Verdemont, we headed back to Devore to see a section of intact 1916 paving, which acts partly as a driveway for an antenna site. The paving, oil macadam, is quite rare to see these days and was pretty cool to see. Despite all it has gone through, the paving was fairly smooth with only a few major potholes. The roadway damage did also offer an opportunity to more closely inspect the paving itself. The aggregate that was used was fairly large by modern standards and appeared to be granite.

Intact 1916 macadam paving at Devore

North on Cajon Blvd, we passed a couple of C-monuments adjacent to the freeway. I first spotted these on a trip a few months ago following the Blue Cut fire. It was nice to see they were still there. Those monuments were also at the point where old Cajon Blvd merges with the “new” Cajon Blvd (the extension from Devore on a new alignment).

Looking toward I-15 at Blue Cut in the former expressway median

Our next stop was at Blue Cut. There, we checked out a plaque commemorating the history of the Blue Cut area. Blue Cut, as it was noted on the plaque, was the location of a toll booth on the original wagon road through here. We also inspected the foundations of the 1940’s weigh station, which was removed not long after the freeway bypassed this section. While we were at Blue Cut, we also watched three trains pass by, one of which was a “fast freight”, which was passing another train.

Salt Lake Trail marker from 1917

Bridge abutments in Crowder Canyon

Moving north from Blue Cut, we stopped briefly at the Debris Cone Creek bridge, then headed toward Cajon Junction. At Cajon Junction, we followed the eastern frontage road south to the end of the road. There, we found the trail monument from 1917, which was placed alongside the roadway just after it was paved. The monument itself was moved to its present location when the freeway was built. This location was also the divergence of the original path through Cajon Pass and the later roads, which eventually became US 66. As it was getting a bit hot, we moved onto our next stop – Cajon Summit.

Between Cajon Junction and Cajon Summit, the old roadway has been greatly modified. Only portions of both directions of the former expressway are still visible. The whole section, however, has been closed since the Blue Cut fire burned the area. This same fire, unfortunately, also took what would have been our lunch stop – the Summit Inn Café. The sign still remains, but the whole business is gone. It may be rebuilt, but only time will tell. So far, the site has only been cleared.

1952 Cleghorn Creek bridge rail

1916 roadway and building foundation

After stopping at the summit, it was time to work our way back down the hill. Instead of taking the freeway back to Devore, we decided it best to take the old highway once again. This time, we made an additional stop at a bridge near Swarthout Canyon Road. This stop proved to be quite interesting as we found the foundations for an old structure that was alongside the 1916 roadway. We figured the old building may have been a gas station or some other roadside service building. We also saw two more trains pass by while we were there.

We headed back to Devore to finish up the tour. By then, we were quite hungry, so we decided to have a late breakfast at Tony’s Diner. The food was decent and the location was nice. It was good to be in a nice air-conditioned building as well. Overall, the tour was a lot of fun, even though it wasn’t well attended. Next time will be better and hopefully be cooler.