58 Adventures in Scenery 



The primitive continent, the ancient Archaean land, was 

 represented in California by small areas that stood above the 

 level of the sea. The backbone of the continent was a ridge 

 which is now the axis of the Rocky Mountains. A large land 

 area, spoken of as the original V-shaped continent, extended 

 from Labrador southwest into what is now the northern United 

 States, and northwestward far toward the Arctic regions. 

 Probably parts of what is now California have been above sea 

 level during all the ages since Archaean time. All lands that 

 are above sea level are subject to the weathering action of the 

 elements and the erosion of streams that flow off the land. The 

 sediments carried from the primitive land areas became the 

 stratified rocks of later formations. 



Cambrian, Silurian, Devonian, Carboniferous rocks now 

 occur in the geologic formations of the State. These rocks are 

 recognized by the fossils that they contain. So also about all 

 the geological formations represented in the great eras of the 

 Mesozoic and Caenozoic down to the Quaternary and Recent 

 occur in the rock formations of the State. The Geological 

 Record, shown in the table of geologic formations, will give 

 some idea of the great length of geologic time. All geologic 

 formations that are shown in the table do not occur in any 

 single geologic section or locality. The formations are not con- 

 tinuous over the State. The Geological Map of California is 

 a rather complicated checkerboard of colors, each color repre- 

 senting a formation. The "formations" were made by the 

 accumulation of mud, sands, and gravels on the bottoms of bays 

 or arms of the sea. It has been stated that there has been land 

 in what is now California since the "beginning." In places the 

 land has been upheaved and in other places the surface has been 

 depressed and covered again by the sea. 



Much granite rock which now forms the surface of the land 

 was forced up from the depths of the earth in a molten condi- 

 tion. The axis of the great Sierra Nevada Range, rock known 

 as granodiorite, was once a molten mass forced up from below, 



