Near Antioch in Contra Costa County, California — The American West (Pacific Coastal)
A Hidden World Awaits
When R. Marvin Greenhouse began hollowing these hills to mine the silica sandstone, he could not have known that the cavernous rooms left behind would fascinate people for decades to come.
Today this portal serves as your gateway to the past and entrance into a unique underground visitor center. Join us during open house, and step into the earth and into the past.
Erected by East Bay Regional Park District.
Location. 37° 57.297′ N, 121° 51.928′ W. Marker is near Antioch, California, in Contra Costa County. Marker can be reached from Somersville Road. Touch for map. Marker is at or near this postal address: 5175 Somersville Road, Antioch CA 94509, United States of America.
Other nearby markers. At least 8 other markers are within 4 miles of this marker, measured as the crow flies. Somersville Townsite (approx. 0.2 miles away); Mount Diablo Coal Field (approx. ¼ mile away); Independent Mine (approx. ¼ mile away); Sidney Flat Black Diamond Way (approx. 3.8 miles away); The Growler Saloon – Goethals Building (approx. 3.9 miles away); The Clayton Post Office (approx. 3.9 miles away); The Joel Clayton House (approx. 3.9 miles away). Touch for a list and map of all markers in Antioch.
More about this marker. This marker is located at the Greenhouse Visitors Center in Black Diamond Regional Park.
Categories. • Industry & Commerce •
Credits. This page was last revised on June 16, 2016. This page originally submitted on April 5, 2016, by Barry Swackhamer of San Jose, California. This page has been viewed 179 times since then. Photos: 1, 2. submitted on April 5, 2016, by Barry Swackhamer of San Jose, California.