Mount Diablo Surveyors Historical Society

Initial Point Celebration
The Mount Diablo Initial Point Plaque Installation
Saturday July 17,1993
Mount Diablo State Park, Contra Costa County, CA
By: Mark Lewis, P.L.S.

I had the opportunity to attend the Mount Diablo Initial Point plaque installation celebration last weekend. There was a barbeque in Mount Diablo State Park with a raffle in the morning and a tour of the museum with the new plaque in the afternoon. I sure had a good time.

To make a long story short, the reason for the new plaque is this: In 1851 Col. Leander Ransom established the Mount Diablo Initial point, for the surveying of the public lands. His monument was a small depression in the highest rock atop the mountain. Then in 1852 R.D. Cutts of the U.S. Coast & Geodetic Survey needed a good spot for a control point so he set a brass cap 3 feet Southeast of Ransom's initial point.

Mount Diablo State Park was dedicated back in 1921, and again in 1931. At some point in time, the visitor's center was built at the top of the mountain around both of these monuments. Unfortunately, a plaque was installed that incorrectly describes how the USC&GS monument (which someone has removed and only the bolt is remaining) is the initial point for the Mount Diablo Baseline & Meridian.

This didn't settle well with my friend John Pettley back in 1985. Well, it's been 8 years, lots of pushing from members of the No. Calif. section of ACSM, East Bay, San Mateo/Santa Clara, and Monterey Chapters of CLSA, some string pulling from Bud Uzes of the State Lands, an AutoCAD drawing from hell, and 3 boxes of paperwork to remove the old plaque and install a new one which reads as follows:

WITH ITS UNOBSTRUCTED VIEW, MOUNT DIABLO'S SUMMIT HAS LONG BEEN AN IMPORTANT REFERENCE POINT FOR LAND SURVEYS IN THE FAR WEST. IN 1851, COL. LEANDER RANSOM BEGAN SUBDIVIDING THE PUBLIC LANDS BY ESTABLISHING THE MOUNT DIABLO INITIAL POINT. FROM THIS POINT, LINES WERE EXTENDED NORTH, SOUTH, EAST AND WEST FORMING A SURVEY GRID THAT COVERS MOST OF NORTHERN CALIFORNIA AND ALL OF NEVADA. THIS POINT IS MARKED BY A RECTANGULAR DEPRESSION IN THE EXPOSED BEDROCK, THREE FEET NORTHEAST FROM THE CENTER OF THIS PILLAR. IN 1852, R. D. CUTTS OF THE COAST SURVEY ESTABLISHED A DIFFERENT SURVEY MARK FROM WHICH HE BEGAN MAPPING THE STATE'S WATERWAYS AND SURROUNDING TOPOGRAPHY. THIS POINT IS MARKED BY THE COPPER BOLT INSIDE THE BASE OF THIS PILLAR.

Inside the museum is an old transit and grunters chain from the late Cecil Hansen's collection donated by his son, and an old field book donated by Bud Uzes.

The installation celebration took place on July 17,1993 and was the 143rd anniversary of Col. Ransom's survey. It was a great summer day in which I had the pleasure of seeing some old friends and meeting some new ones.

Thanks and congratulations to John Pettley, Steve Wilson, Myron Lewis, Mount Diablo Surveyor's Historical Society and everyone else who made it happen.

Reprinted from the Fall 1993 Issue, # 102 of the California Surveyor “Letters To The Editor” section with edits by Michael J. Foley, PLS, all rights reserved.

To read the full text of the plaque, click here. To see a photo of John Pettley with the plaque and its location on the piller

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