CCCHS presents The Story Behind the Initial Point atop Mount Diablo

CCCHS Author in the Archives Series presents

John Pettley, a professional land surveyor for over 38 years, talks about the significance of his amazing find in 1987. At the time, John was a surveying student at California State University at Fresno, and working on his senior thesis, when he made an important discovery about the history of the survey marks atop Mount Diablo.

On July 18, 1851, Col. Leander Ransom of the General Land Office (GLO) labored through thick brush, steep terrain, and harsh summer heat to establish the initial point on the highest rock at the summit of Mount Diablo in Contra Costa County. There he chiseled a hole in the rock and erected a pole with a large flag that could be seen for miles from the surrounding countryside. The grid lines intersected at the Initial Point on the summit of the mountain.

This mapping grid was extended to cover most of Northern California and all of Nevada and was used in deeds to describe the property boundaries in those areas. References to this system are found in numerous property deeds even to this day.

Step back in time with us as we hear the fascinating story of John’s journey in rediscovering this important piece of California and Nevada history!

Doors open at 4:00 p.m. John’s talk begins at 4:30 p.m.

Admission is FREE for CCCHS members, $10 for non-members.

RSVP is requested. Reserve your seat and purchase tickets at this link on Eventbrite.com. Questions? Call (925) 229-1042 Tues-Thur 9am-4pm or email us at mkting@cocohistory.org.

• Beverages and snacks will be available for purchase at the Campbell Theater lobby bar. 
• Complimentary waters provided by CCCHS.
• Downtown parking is free on weekends.

‍All proceeds benefit the preservation work of the Contra Costa County Historical Society.