Geology of the Area:
The mountains contain a rich outcropping of the Latham shale, known for its diversity of lower Cambrian fossils. The fossils are approximately 518 million years old. The Latham shale borders the Cadiz and Chambless Formations, both named after the small towns nearby. However, the land has become part of a nationally preserved area, so the BLM recommends only one trilobite per person.
The most common fossils in the shale are trilobites of the Olenellina genus, which are distinguished by their lack of facial structures, and the cephalon or head molted as a single piece. However, brachiopods including some of the earliest articulate brachiopods (meaning they have hinge teeth) have been found in the Latham shale. Hyoliths, trace fossils, and very rarely an Anomalocaris specimen are in the shale at the Marble Mountains.
According to the Bureau of Land Management, “This area can be found by taking historic route 66 to the town site of Chambless then taking Cadiz Road approximately 4 miles south. At this point the road turns sharply to the left (east) You will see Cadiz Farms housing on the left side of the road. Continue on east for two miles and just before reaching the rail road crossing turn north on Route (Rt.) NS376 for .4 miles at the intersection with Rt. NS299 drive east for .2 miles. your final turn will be north on NS380 for .7 miles park here near the base of the mountain and hike west to east along the wash. Hiking up the mountain and looking down hill will allow you to see where others have excavated pits in the shale and help indicate where fossils have been found.”
Ben Waggoner, “The Marble Mountains,” (UC Berkeley 2000) <http://www.ucmp.berkeley.edu/cambrian/marblemts.html>
“Trilobites in the Marble Mountains, Mojave Desert, California,” <http://inyo.coffeecup.com/site/latham/latham.html>
“Needles Field Office Rock Hounding,” (Bureau of Land Management 2015) <http://www.blm.gov/ca/st/en/fo/needles/rock.html>