| Trilobite Wilderness | |
|---|---|
 Sign welcoming visitors to the area | |
   | |
| Location | Mojave Trails National Monument, San Bernardino County, California |
| Nearest city | Chambless, California |
| Coordinates | 34°38′24″N115°33′0″W / 34.64000°N 115.55000°W /34.64000; -115.55000 |
| Area | 37,308 acres (150.98 km2) |
| Established | 31 October 1994 |
| Governing body | Bureau of Land Management |
TheTrilobite Wilderness is a wilderness area in theMarble Mountains of the easternMojave Desert in northeasternSan Bernardino County, California. It is named for the large number oftrilobite fossils that can be found within its boundaries. Aside from itspaleontological significance, it is home to typical flora and fauna of the Mojave Desert, including a stable population ofbighorn sheep anddesert tortoise.[1][2] The area was created as an addition to theNational Wilderness Preservation System in 1994 as a part of theCalifornia Desert Protection Act.[3]
The site is managed by theBureau of Land Management. It is one of six wilderness areas inMojave Trails National Monument, established in 2016.
In the earlyCambrian, fossiliferoussediments from a shallow sea were deposited upon abasement ofProterozoic granite and lateruplifted to form theMarble Mountains. These sediments – theLatham Shale Formation – are between 50 ft (15 m) and 75 ft (23 m) thick. Deeper sediments weremetamorphosed intoquartzite and form a thin layer ~10 ft (3.0 m) thick between the shale and basement granite.[4][5]
The abundance of trilobite fossils, some measuring as long as 8 in (20 cm), give the wilderness area its name – in places virtually every piece of extracted rock contains pieces of fossil trilobite.[6] Trilobites from the orderOlenellina are predominant, but 12 species of trilobite have been discovered in this area. Full specimens are rare, with trilobite heads being the most commonly found feature, potentially indicating the area was the site of a trilobitemolting ground.[7][5][4] In all, roughly 21 species of Cambrian invertebrates have been discovered in the area, includingarticulate brachiopods andAnomalocaris appendages.Oncolite fossils are also found in significant quantities.[7][8] This makes the area abucket-list location for trilobite collectors worldwide.[6]
