The field work on which the following report is based was done in conjunction with a reconnaissance survey of the Bengal quadrangle,1 California, which is now in progress for the California State Division of Mines. Because the work on the Paleozoic rocks of the area has progressed most rapidly in connection with the Middle Cambrian formations, it has been deemed advisable to summarize the results so far obtained. In a sense, this report is a continuation of a paper by Hazzard and Crickmay 2 in which the lithology and fauna of the lower portion of the Cambrian succession of this region were discussed.
The Providence and the Marble mountains are about seventy miles west of the Colorado River, within the northern half of the Bengal quadrangle. The Providence Range lies east of Kelso, California; the Marble Mountains are about thirty miles farther south. The writers wish to thank C . . .