UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGICAL SCIENCES 



Vol. 13, No. I, pp. 1-7 December, 20, 1921 



LOWER AND MIDDLE CAMBRIAN FORMATIONS 

 OF THE MOHAVE DESERT 



BY 



CLIFTON W. CLAEK 



CONTENTS 



Introduction 1 



Occurrence of formations 2 



Geological relations 3 



The invasion of marine waters 3 



Pre-Cambrian granite 3 



Lower Cambrian 3 



Middle Cambrian 4 



Carboniferous .". 4 



Bristol Mountain section 5 



Faunas 6 



Lower Cambrian 6 



Middle Cambrian 6 



Carboniferous — 6 



Correlation 7 



INTRODUCTION 



Paleozoic sedimentary rocks are exposed in Bristol Mountain 1 in 

 Mojave Desert near the town of Cadiz on the Santa Fe railroad, about 

 100 miles east of Barstow, California. Darton 2 first described these 

 rocks in 1907 and again in the Santa Fe Railroad Guide in 1915. 3 



In 1915, Mr. 0. A. Gavins, a student in the University of California, 

 while studying the geology of this region, discovered a shale bed con- 

 taining Lower Cambrian fossils. From the study of a small collection 

 made by Mr. Cavins the writer became interested in the region and 

 spent about two weeks visiting various exposures and obtaining a 

 collection representing the fauna. 



1 The Iron Mountains referred to by Darton in the Santa Fe Eailroad Guide 

 for 1915, will be called in this paper Bristol Mountain, the name given to the 

 range on the official map of San Bernardino County. This map also gives to 

 the lake at Amboy, 14 miles west of Cadiz, California, the name, Bristol Lake. 



2 Jour, of Geol. vol. 15, p. 470, 1907. 



a U. S. Geol. Surv. Bull. No. 613, Part C, Santa Fe Eoute, 1915. 



