Age of the California Coast Ranges. — Fairbanks. 281 
gave the Great Valley a form approximating that of the presr 
ent day, and there is every reason to suppose that this valley 
has been subject to continuous sedimentation up to within 
comparatively recent geological times. But whether continu- 
ously submerged or not, when once the folding of the crust 
was initiated along the axis of the Coast ranges it is in the 
last degree improbable that the axis has ever been wholly ob- 
literated. 
Summary. In the Coast Eange region a granitic axis is 
recognized as existing above water and undergoing erosion in 
early Mesozoic and possibly Paleozoic times. 
Preceding the deposition of the Golden Gate series, whicl^ 
is believed to represent the upper Jurassic, a subsidence tool? 
place continuing with oscillations to the close of that period. 
At the termination of the Jurassic occurred the great up- 
heaval of the Sierras and Coast ranges. The Golden Gate 
series after being uplifted and folded was subjected to a con- 
giderable interval of erosion, following which another depres- 
sion took place. 
The Cretaceous was ushered in with a sinking land. This 
(?ontinued through the Knoxville when another elevating 
movement was experienced. Through the central portion of 
the Coast ranges the Knoxville was thus subjected to disturb- 
ances and erosion, causing a stratigraphic break between it 
and the Chico. During the latter period a subsidence was 
again inaugurated until the opening of the Eocene when the 
re-elevation of the land in northern California was probably 
felt through the whole of the Coast ranges. 
At the close of the Eocene we have evidences of a renewed 
disturbance which resulted in the strata of that age being 
folded, uplifted and exposed to erosion. 
Miocene sandstones are found resting with marked non- 
conformity on the Eocene in the southern Coast ranges, point- 
ing to the fact that still another depression had been expe- 
rienced with the opening of the Miocene. Sinking continued 
through this period and at the time of change of sedimenta- 
tion from sandstone or clay to the bituminous shales, exten- 
sive movements similar in character to those shown in the 
Golden Gate series must have taken place. The Miocene was 
terminated by one of the most marked changes of level record- 
