Calaveras County, CA
By Bruce Rogers
White settlers apparently (re)discovered this little cave near Mountain Ranch on April 30, 1850 and named it Cave of the Catacombs according to a short note in the Alta California newspaper. Mr. Lane, a merchant, and Mr. McKinney, both of Mokelumne Hill, were these discoverers (nearby McKinney Creek was named after Mr. McKinney). The original explorers remarked on the large quantities of stalactites (everything attached to the ceilings and walls of caves were referred to as stalactites in that time period) and indications of gold in the sediments. Shortly after the cave’s discovery, several local miners entered the cave and panned the floor sediments looking for gold; they were disappointed. Subsequently, its location was lost and, indeed, the travel writer and California booster J. M. Hutchins does not mention the cave in his 1872 Scenes of wonder and curiosity in California book.
Cave of the Catacombs has also been known as Miller’s Cave–named after Mr. Jerry Miller, the 1950’s owner of the property. In November of 1951, the Stanford Grotto visited the cave armed with an August 15, 1881 San Francisco Call newspaper account and sketch map of the cave, exploring the cave, and mapping its length of approximately 430 feet of passage. After comparing the etched signatures in the cave and excavating the blocked, eastern entrance, they realized that this was the original Cave of the Catacombs.
The cave is located in a low, partly vegetated marble hill adjacent to a small topographic amphitheater. Considerable native and introduced grasses, shrubs, and trees cloak most of the hill. Buckeye (Aesulus californica), poison oak (Taxicodendron diversalobum), and other low trees and shrubs are the predominant cover. The several lakes in the cave apparently are reflections of the local water table. In extreme drought years, the main lake occasionally dries up while in wet El Nino years most of the cave is flooded.
The bedrock is marble of the Calaveras Assemblage, a unit that dates from the Permian Period in age, between about 298 and 252 million years ago. We know the age of this rock unit because rare “ghost” fossils are very sparsely found within it. Solitary horn-shaped corals with a diameter of a half dollar coin can be found as ghostly circular structures exposed on the surface of the rock. When examined in detail, they show no actual structure, probably being only a chemical signature of their former selves. At that time the area that is now California lay off the western shore of the super continent Pangaea, covered by the globe-encircling Panthalassa Ocean. In that environment, shallow banks of lime mud and shells accumulated and were later consolidated into limestone. During the succeeding several hundreds of millions of years, earth movements rearranged the continents and the limestone was heated and compressed into marble. Later volumes of magma rose in the crust and cooled to form granitic rocks and also melted most of the older sedimentary rocks including much of the limestone. This metamorphism also baked the limestone and dolomite into marble. Later uplift and erosion stripped most of these rocks away, leaving only scraps of the marble behind floating in a sea of granitic rock. Slowly percolating ground water, enriched with dissolved carbon dioxide from soil bacteria, gradually dissolved the marble along nearly vertical cracks (called joints) and formed the cave. After the cave breached the surface and allowed the carbon dioxide-charged cave air to mix with the atmosphere, the water composition changed and it dropped its dissolved mineral load as cave decorations called speleothems.