Welcome to the University of California White Mountain Research Station (WMRS) website concerning early Paleozoic arthropods affectionately known as Trilobites. The Trilobite fauna that you can view on these pages lived in a marine environment al least 530 to 500 million years ago in the area now occupied by the Inyo-White Mountains. Specimens that can be viewed on this digital archive are also available at WMRS for examination by paleontologists and students of the Cambrian period.
This website is dedicated to the pioneering efforts of Professor Clem
Nelson, Emeritus, UCLA
who was the guiding light for innumerable students of the ancient seas and enchanting Inyos for the last 40 years.
Map showing the location of the Blanco Mountain area in the Inyo-White Range, Eastern California
A simplified geologic map that shows the distribution of granitic rocks (red) Precambrian strata (brown), Paleozoic strata (blue), Mesozoic strata (green) and Cenozoic strata (yellows) and location of Trilobite samples from the Inyo-White Mountains. Early Paleozoic, Cambrian marine strata are found throughout the southwestern United States from the Sierras to the Colorado Plateau. These rocks are multiply deformed and intruded by Mesozoic plutonic rocks. The present day topography is a consequence of Late Cenozoic high-angle, oblique-slip faulting in response to interaction between the Pacific and North American Plates.
The Cambrian stratigraphy of the Inyo-White Mountains was first describe by Walcott, in the late 1800's. The Cambrian sedimentary rocks represent diverse marine environmental conditions that mainly reflect changing sealevel in response to episodic climate change and isostatic subsidence due to loading of the clastic sediments on the continental shelf. There was no tectonic activity along the continental margin during this time. The lithologic units, Formations, that are subdivided in the Cambrian strata are characterized by different amount of fine-grained lithic sediment relative to carbonate sediment, and by different grain size of the sediment that was deposited. The differences in the type of sediment and the associated sedimentary structures reveal the nature of the changing marine environment through time.
Trilobite samples from the Inyo-White Range collected by Prof. Clem Nelson, his students and associates are presently archived at the University of California, White Mountain Research Station in Bishop. Digital images of the archive, along with a description of the sample condition and archive number can be viewed.