Calling all history buffs: it’s time for another History Mystery, Press readers, and once again local historian Carol Jensen has supplied us with another historical postcard, inviting readers to identify the people in the photograph.

This month’s mystery features the John Marsh House, a Contra Costa landmark built in the 1850s. Marsh, a doctor, was the first settler in what we know today as Contra Costa County. His letters to friends on the east coast helped propel the westward movement, and he became an influential man and aspiring politician.

Marsh built a large mansion on his Los Meganos property to enhance his political ambitions by showcasing the success he had achieved since moving to the area in 1836. His ambitions were short lived. Murdered while in route to San Francisco in September of 1856, Marsh never moved in to the impressive stone house.

The card displays the image of a man preparing to take a photograph of six people relaxing on the front porch of the Marsh House. The card bears no message on the back and no postal marks.

Jensen has good reason to be especially curious about this image. She is a member of the John Marsh Historical Trust, a nonprofit organization collecting funds to restore the Marsh House to its original condition.

“There are several points of interest in this card,” said Jensen. “First, what year was the photograph taken? We know the image was taken after the year of the ‘great earthquake’ (of 1868), as the Romanesque, crenelated top of the tower fell and a wooden tower later replaced the original stone. But what year specifically?”

Jensen also wants to know about the people in the photograph. Although Marsh never lived in the house, his family did. Local ranchers eventually lived in the house while Marsh’s son Charles decided what to do with the property, so Jensen wants to know if the people in the photograph could be someone’s grandparents posing for the photo.

Finally, Jensen wants to know if anyone can identify the man behind the camera at the front door. She suggested that some early California photographic historians or enthusiasts might recognize him.

The first person who provides substantial information about the individuals in the photograph, including the photographer, will win two tickets to the John Marsh Historic Trust Gala on Sunday, Oct. 17. The prize is valued at $150. To share information about this historic photo postcard, e-mail Jensen at historian@byronhotsprings.com.

The gala, a fundraising event sponsored by the John Marsh Historic Trust, will be held from 1 to 4 p.m. at Club Los Meganos, Trilogy at the Vineyards, 1700 Trilogy Parkway in Brentwood.

An informational presentation will be held during the gala regarding plans for the future of the John Marsh House. All proceeds benefit the John Marsh Historic Trust’s effort to stabilize and rehabilitate the house.

For tickets to the gala, call Becky Bloomfield at 925-783-0050 or e-mail marsh1856@yahoo.com. Tickets are $75. Personal checks, debit cards, credit cards and PayPal are all accepted. Additional tax deductible donations, payable to the John Marsh Historic Trust, P.O. Box 272, Concord, CA 94522, are appreciated.

For more information about Marsh and the Trust, visit www.johnmarshhouse.com.