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.
Topics. This historical marker is listed in this topic list: Industry & Commerce.
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. Touch for directions.
Other nearby markers. At least 8 other markers are within 4 miles of this marker, measured as the Somersville Townsite (approx. 0.2 miles away); Mount Diablo Coal Field (approx. ¼ mile away); Independent Mine (approx. ¼ mile away); Sidney Flat (approx. 1.2 miles away); Black Diamond Way (approx. 3.8 miles away); The Eucalyptus Grove (approx. 3.9 miles away); The Growler Saloon – Goethals Building (approx. 3.9 miles away); The Clayton Post Office (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.
Credits. This page was last revised on June 16, 2016. It was originally submitted on April 5, 2016, by Barry Swackhamer of Brentwood, California. This page has been viewed 275 times since then and 24 times this year. Photos: 1, 2. submitted on April 5, 2016, by Barry Swackhamer of Brentwood, California.