The Geologic Map 91 



Thus it is seen that much disturbance has occurred by which 

 the distorted, folded, and broken conditions shown in the cross 

 sections came to be. The areal geology map shows the rocks 

 that now occur at the surface. All are more or less obscured 

 by the mantle of soil which has resulted from the weathering 

 of the exposed rocks. 



A Segment of the State Geologic Map 



In figure 27 a part of Inyo County is represented, from the 

 State Geologic Map. This segment of the large State map will 

 give some idea of the long history of California. Very old 

 rocks, and very recent formations are shown. The different 

 formations are indicated by numbers. 



On the State geologic map of California about all the geo- 

 logic formations of the earth are represented, though the 

 "beginnings" of California are involved in much uncertainty. 

 Whether rocks of the primitive Archaean the oldest known 

 rocks in the world occur amongst the ancient granitic forma- 

 tions is not with certainty known. That later Archaean 

 (Algonkian) rocks occur in the granitic basement complex of 

 the Coast Ranges seems reasonably certain. The very ancient 

 sedimentary formations of the Cambrian, and about all succeed- 

 ing sedimentary formations, occur in California. Extensive 

 deposits of older formations it is thought are buried beneath 

 later deposits. Some of these have been uncovered by erosion 

 and so appear on the geologic map as surface formations. Very 

 old Cambrian, or pre-Cambrian, rocks, much crumpled, folded, 

 and metamorphosed, occur in southern California. On the 

 western slope of the high Sierra Range, and farther north in the 

 vicinity of Mount Shasta and the Klamath Mountains, ancient 

 sediments of the Palaeozoic era occur. The Cambrian seas may 

 once have covered large areas in central California. Much rock 

 then formed has been buried under younger formations, or has 

 been eroded and carried away. 



