68 Adventures in Scenery 



and shattered schists, crystalline limestones (marble) , quartzites, 

 and other metamorphic rocks that today occur over wide areas 

 in the mountain districts. These metamorphosed ancient sedi- 

 mentary rocks, together with the granite which was forced up- 

 ward in molten condition and intruded into them, now form 

 what is called the "basement complex" or bed-rock of the Coast 

 Ranges and of the Sierra Nevada. This bed-rock, or basement 

 complex, forms the core or axis of the great mountain ranges 

 of the State. It extends continuously from the southern Sierra 

 Nevada, in the region of Mount Whitney, around the southern 

 end of the Great Central Valley into the Coast Ranges where it 

 becomes the bed-rock or basement upon which the Franciscan 

 rocks rest unconformably. 



After a long time of cooling of the intruded molten mass, 

 and during long ages, the overlying sedimentary rocks that were 

 intruded by the molten granite were worn by weathering and 

 erosion, and in time were entirely removed over wide areas, so 

 that the once molten rock, now cooled and forming the crystal- 

 line granitic rocks of the basement complex, has been exposed 

 over wide areas, and now forms the rugged granitic rocks that 

 characterize the mountain ranges. 



Franciscan Rocks Rest upon Basement 

 Complex 



Upon the eroded surface of the basement complex of plu- 

 tonic and metamorphic rocks rests the Franciscan. In the cen- 

 tral Coast Ranges, over wide areas, erosion has completely re- 

 moved the sedimentary rocks, uplifted, folded, crumpled, and 

 broken, which were intruded by the molten granite. The time 

 required for the complete removal of these early sedimentary 

 beds must have been very great. A fact of great interest is that 

 in very early geologic time, that is during the Archaean or 

 Archaeozoic era, land existed in the Pacific border region. The 

 boundary of the continent was much as now. The absence of 



