A fossil enthusiast digs into crumbly, poorly exposed early Cambrian sedimentary rocks during a weekend outing in the Marble Mountains trilobite quarry. Please note that this photograph was taken long before the Marble Mountains became part of a national monument.

The Marble Mountains trilobite locality presently lies within Mojave Trails National Monument (officially authorized and established on February 12, 2016), where the BLM (Bureau of Land Management) continues to allow the casual collection of reasonable amounts of common invertebrate fossils--a designation that here includes trilobites; for fossil sites situated on private property, visitors must secure explicit permission from the land owners.