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  • Writer's pictureDale Hill

Daily Double: Volcan Benchmark

Date: January 4, 2021

Distance: 5.83 miles

Total Elapsed Time: 3h 18m

Total Moving Time: 2h 38m

Summit Elevation: 5,328 feet

Elevation Gain: 1,148 feet

Trailhead: Farmer's Road

Previous Ascents:

  1. February 8, 2020

  2. August 9, 2020


  1. This is the second of two peaks for the today 😉

  2. Survey Markers - 9 (including two that I'd recovered previously and a Bonus"drive-by" on the way home)

I really enjoy this hike, the trailhead is only about 35 minutes from my house, it's not a super technical or difficult hike, and the views are always spectacular. After completing Cuyamaca Peak this morning with a good part of that hike in the snow, I wondered what the trail to Volcan Benchmark would be like.

As with my morning hike, I had two primary goals for this trip. First, bag the peak for the San Diego Six-Pack of Peaks Challenge (my fourth), and second, look for survey markers that I either overlooked or couldn't find on previous trips.

Mission accomplished! This peak had me back on track with my self-imposed goal to complete the 'San Diego Six' in as many days, it's January 4th and I've completed the first four peaks. We'll see if I can complete the last two in the next two days!

In addition to "rediscovering" two survey markers that I'd found before, I recovered six new ones, including two Section Corners on the way to the summit, but more on my survey marker recoveries in a bit.

There wasn't nearly as much snow on this trail as there was on Cuyamaca but, I did slip my microspikes on just past the turn-off for the Five Oaks Trail. The road was muddy in places with patches of ice and the added traction of the microspikes allowed me to cruise right up the trail with no issues. Since it was late in the day, everyone I passed was coming back down from the summit, the majority of who were walking dogs. Just past the spot where the Five Oaks Trail rejoined the main trail, I met a guy who warned me of a mountain lion he saw near the summit.

Two "Found" Section Corner Marks

I have really come to enjoy looking for Corners Markers, they can be for Townships, Sections, or Quarter-Sections. Technically speaking, if they're there, they shouldn't be terribly hard to find. Of course, not EVERY section corner in the country has a nifty engraved and stamped brass disc to tell its story, but the diversity in what I do find is what makes them all the more interesting. My first find was about a half-mile up the trail, and about 350-feet off the centerline. Not surprising, there was a faint trail that led almost directly to the marker, I say 'almost' because I could see the witness stake in the barbed-wire fence on the steep sidehill, about 40 feet down, through a LOT of brush. Oh well, I'd come that far and I could see the witness stake, so I forged ahead. This one was an iron spike driven into the ground, it looked to be about ¾" square that marked the corner between sections 19, 20, 29, and 30 in Township 012S 004E.

The second one was roughly half the distance between the old chimney stack (the only remains of the Volcan Mountain Observatory Outpost) and binocular viewpoint, on the other side of the road, about 200 yards to the East. It is actually visible from the road if you know what you were looking for.

I had left the road right by the chimney stack and crossed over into the field to search for the Volcan Azimuth Mark so I was already out in the tall grass when I saw the witness sign across the field. It checked with the general location of the corner and I worked my way across the field towards it. There were a couple of coyotes on the hill beyond the sign, but they ran off as I approached. As I got closer to the signpost, I realized IT was the corner mark, It was a standard USFS Location Poster with a tack showing the position of the corner, Township 012S 004E, Sections 20, 21, 28, and 29.

Volcan Azimuth Mark

I had a general idea of where the Azimuth Mark was based on a description I read in the datasheet, I knew it was mounted in the top of a boulder about 18" high, that it was the west-most boulder in a small group of rocks, located about 50 feet off the road. I hadn't thought to plot the Azimuth ahead of time, but knowing that the field was pretty open and the boulder piles few and easy to locate, I didn't think I'd have any trouble finding it. Well, I went from rock pile to rock pile, scanning the tops of all boulders and rock outcroppings - no luck. This one would remain "unable to locate" until I could come back with the exact Azimuth bearing.

Not close enough for a good picture

I headed back across the field towards the trail and on to the summit. As I was crossing the field I did spot the mountain lion up on the hill west of the trail, easily a couple of hundred yards from where I was. It was well off the trail, but my plan was to make plenty of noise as I approached anyway.

I encountered a young couple right after I passed the binocular viewpoint. I mentioned that I saw the mountain lion from a distance and wondered if they had seen it, they had not, which they chalked up to the fact that there were two of them and they were intentionally making a lot of noise, but I did note they were each carrying decent sized rocks in each hand 🤔 As it turned out, there was no sign of it when I finally made it to the summit.

Summit Survey Marks

On my first trip to Volcan Benchmark in February 2020, I easily located the most photographed survey marker disc on the peak, it's really hard to miss as the trail loops around the summit, it's mounted in a concrete pillar about 18" high just slightly above the trail. This is often mistaken as the Station Disk and is usually referred to as the Norman Glover disc, named for the Land Surveyor who originally set the disk.

In 2020, I didn't realize the Airway Beacon at the summit was actually a survey mark, I took lots of pictures of it and the interpretive plaque because I thought it was a cool piece of history. However, on this trip, I knew that it was a marker in its own right with a Permanent ID assigned.

San Diego GPS Station 14

As I walked around the South end of the summit I noticed a small painted rocking sitting on a big boulder by the trail (it's a thing to leave painted rocks along the hiking trails for other people to find and reposition somewhere else). I usually just look at them and leave them for the kids to find. This particular one was a memorial stone for someone who passed away. Out of respect, I left it be and didn't photograph it. However, I did notice that it was sitting about six inches from a 2" brass survey disc mounted in the boulder!

Placed in 1990 by the SD County Engineering Department, it was stamped HPGN-CA SDGPS14 RM 2.

HPGN stands for High Precision Geodetic Network and includes passive marks used by the GNSS or Global Navigation Satellite System. I poked around the area and found HPGN-CA SDGPS 14 RM 1 a little further down the trail. (Once I got home and researched these, I discovered that I missed the HPGN-CA SDGPS 14 station!) I’ll have to recover it next time.

US Geodetic Survey Station and Reference Marks

While researching the NGS site and the datasheet for Volcan, I was surprised to learn that the Glover disc wasn't the main station disc, there was a USGS Triangulation Station disc with two standard Reference Marks (RM 1 and RM 2). Knowing that the summit area is not that large, I figured I ought to be able to use the station coordinates and just put in some time searching the area to locate all the marks.

From everything I could tell, all of these marks were in the stand of trees next to the Airway Beacon on the summit (first image below). On the western side of the summit loop, there's an informational sign, picnic table, and a concrete slab from an old structure. Next to that slab is a little trail that leads up into the trees. It didn't take much time to locate the two USGS Reference Marks, especially since I knew they were mounted in boulders and as I mentioned, the area just isn't that big.

With both reference marks found, it SHOULD have easy to locate the station disc, after all, that is the purpose of the reference marks. When the reference marks are set, the arrow stamped in the disc is oriented to point directly at the station disk, reference marks are usually set far enough apart so that they form a triangle with the station disc (hence the term Triangulation Station), I didn't have my print out of the data sheet with me and I couldn't remember how far each reference mark was from the station disc, but how hard could this be right?

Obviously, harder than I expected. I used my trekking poles to lay across the top of the reference marks like giant compass needles then sighted along them to find the approximate intersecting point. This got me close, but the snow was deep and the scrub brush was thick. There were lots of boot prints in the snow all over the area where I was (I suspect from others who searched for it too), but I couldn't see where anyone had located it. I decided to call off my search and come back when the snow was gone and I could see what I was looking for. Still, I had two new USGS recoveries, not a bad result!

Overall, it had been a good day, I'd added two more peaks to my 'done' list and I'd found a lot of new survey markers between my two hikes. Content, I headed down the trail at a good pace so I would finish up in daylight.

The Volcan Gateway


Driving home, I had my GAIA GPS app open and in 'follow' mode as I usually do scanning for potential benchmarks along the way. As I approached the Inaja Memorial Park on a small peak overlooking Santa Ysabel, I saw the benchmark notation on my map so I pulled into the parking area.

This was a super easy recovery and another piece of history that I probably would never have paid attention to if I hadn't been searching for survey marks. The stone monument was erected in honor of 11 men who lost their lives fighting the Inaja Forest Fire Thanksgiving weekend in 1956.

This is a RESET disc, at the time I didn't know where the original F 308 disc was located (or if it still existed) so I didn't attempt to look for it. After getting home and doing some research, the original station was less than 100 feet away on the top of a large rock outcropping. I'll have to stop by and look for it next time I'm out that way.

Relive® 3D Video of Toady's Trip

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