Home | Columns | History Mystery | Books | Speeches | Time Capsules | Oral History | Biography | Links

Barry Schrader


I currently have columns running in 3 newspapers;

  • Tri-Valley Herald : Looking Back
  • Valley Times : Do You Remember?
  • The Independent : Do You Remember?

The Articles appear in the Herald and Independent on Thursdays,
and the Times on Sundays.

They will also be found on this page each week as well.


If you've missed any please follow the links on the dates to catch up.

Archive Page

Historic benchmarks along the road

By Barry Schrader.................................February 2, 2006

How many times have you been atop Mt. Diablo and never saw the geodetic marker? That’s the brass disk embedded in cement inside the stone building. This disk was placed there in 1852 by surveyors from the US Coast & Geodetic Survey, only two years after our statehood. And that was a long time before the building was located on that spot.

The significance of this survey marker, known as a benchmark, is that all of Northern California was mapped using this as the land control point which determined the borders of all townships, sections and even private property lines. The location gave a straight line view all the way to Mt. Lassen and Mt. Hamilton on a clear day.

Ken Lamb, now retired, but at one time the City of Pleasanton’s surveyor and traffic engineer among other things, has spotted dozens of these small brass or iron disks, about three-and-a-half inches across, while doing surveying or just driving through the countryside. He recalls one on top of Crane Ridge and others along the Pleasanton Ridge. After leaving the city job he formed Lamb Land Survey and spent years spotting more markers, some more difficult to locate than others. Since most of them were installed 50 to 150 years ago, geography has changed, roadways have been built or widened, railroad tracks moved or torn up, and structures built where the markers used to be set in concrete a little above ground level.

I then learned from my Heritage Estates neighbor Steve Gawura that the Power Squadron, an organization of sail and power boat enthusiasts, had adopted a nationwide project of locating and reporting all the remaining benchmarks in the country that can be found. In the last 20 years Steve himself has tracked down hundreds of these little brass disks (they were made of iron during World War II though) and even a few months ago did some sleuthing around the East side of Livermore. He adds that many water towers, church spires and other tall structures have also been used by the Geodetic Survey as reference points. Each benchmark disk is given a Permanent Identification Number (PIN) stamped on its surface or painted on the cement in which it is imbedded as well as the date of its original placement.

With his GPS unit (Global Positioning System) it was easy to find two on Greenville Road. The most evident one along the roadway is on the west side of Greenville across from Lupin Way as you enter the LLNL East Gate. Near the roadway you can see a metal post and right next to it embedded in a cement base is an iron disk (placed during WW II in 1944). Get up close to read the sign on the stake and you will find it says “Witness Post” which is the name of those remaining stakes that help pinpoint the location of the ground-level markers. North of there on the same side of the road, across from Old Patterson Pass Road, you will find a second one. But the Witness Post has been bent over by an accident at some point.

The one in the Amador-Livermore Valley probably the most frequently passed by unaware motorists is on Stanley Boulevard. I know I have driven that road hundreds of times and never paid any attention to two concrete pillars about three feet high next to the westbound lane. If you check your car odometer, it is exactly one mile west of the traffic signal at Stanley and Isabel. You will see the initials “BM” and a number painted in white on the one pillar and if you can safely pull off the road there you will find the benchmark embedded on top of the cement block, dated 1947.

If you are not satisfied locating just a couple of these, then go to the website at www.ngs.noaa.gov/cgi-bin/ds_radius.prl and you can find the locations of hundreds, maybe thousands more. At the latest count in December 2005 there were 736, 425 spread throughout the US. And if you really like a challenge, climb Half Dome and find the one there. I learned of its existence while in the cocktail lounge at Yosemite Lodge a year ago. Used as decorations in the top of the bar were benchmark disk replicas from around the Park. I found you can also buy them for $39 in the gift shop next door.

Steve related one of the most unique experiences he had years ago while tracking the elusive little disks in Durango, Colorado. Their team zeroed in on a marker that was supposed to be on the side of a schoolhouse in town. They found the coordinates and it appeared the brass disk was buried under a dozen layers of paint on the wall about four feet above ground. As they struggled to chip off the layers the school janitor confronted them to demand to know what they were doing to the side of his building. As they were trying to explain the significance of this “historic marker” the school principal arrived on the scene to investigate the matter. After they gave her the full explanation she was thrilled to know they had found such an historic piece of Americana on her building that her students could learn about.


Now here’s a history mystery for Sandia National Lab employees to solve. According to federal records there is a benchmark disk on their site somewhere 25 feet west of Avenue A on the concrete surrounding a manhole cover. The GPS coordinates are North 37 degrees, 40 minutes, 48 seconds, and West 121 degrees, 42 minutes, 21 seconds. Will someone there be able to find it or is it long gone? It was installed in 1957, just a year after Sandia was founded in March 1956 (which happens to be 50 years ago this Spring).


The columnist can be reached via email at :


or by snailmail at:

Barry Schrader
PO Box 446
Livermore, CA. 94551

Home | Columns | History Mystery | Books | Speeches | Time Capsules | Oral History | Biography | Links