TOE MIOCENE. 219 



Ranges. In certain localities, however, as at New Idria, Mt. Diablo, and the 

 Blue Range on Cache Creek, northeast of Knoxville, these effects can be 

 somewhat satistactorily compared, and it tlien appears tliat the Tertiary 

 upheaval, important as it was, was far less violent than that, wliich took 

 place near the beginning of the Cretaceous. The extraordinary crushing 

 so conspicuous in the Knoxville beds, and in which an almost inconceivable 

 amount of energy must have been expended, is not observable in the dis- 

 turbed strata of later age, which, as a rule, tliough inclined, form large 

 adherent masses with gentle curves interrupted only at long intervals by 

 faults. The beds from the Wallala to the Miocene are sometimes nearly 

 vertical, but more generally lie at an angle of less than 45°. Along the 

 western base of the great Sierra the effect of the Post-Miocene upheaval 

 of the stratified rocks is, so far as I know, scarcely perceptible. It does 

 not follow that it produced no effect in this region; on the contrary, the 

 absence of known Pliocene beds from tlie Sierra foot-hills seems to show 

 that the range was raised considerably at this epoch, though the energy of 

 this movement was insufficient to produce considerable flexure in the beds. 

 At the eastern side of the range, on the other liand, the fresh- water Truckee 

 Miocene beds were thrown into bold folds, their dip reaching 30^.' The 

 same upheaval was felt thoughout western Oi-egon, where it had the same 

 comparatively gentle character as in the Coast Ranges. 



Pliocene and Post-Piioceno strata. — Plioceue bcds, iu part of uiariue origin, were 

 shown by Professor Whitney to exist at a number of points in the Coast 

 Ranges. None of these is included in the areas surveyed in connection 

 with tliis memoir. An interesting fresh-water series, however, occurs to 

 the east of Clear Lake,= about the north fork of Cache Creek. The beds 

 belonging to it are entitled Cache Lake beds on the map of the region 

 accompanying this volume. They are composed of gravel, sand, and 

 calcareous beds, partially indurated in spots, probably b}' the action of 

 humus acids.^ These beds appear to have a great thickness when meas- 

 ured perpendicularly to the dip, which varies from 10° to 40°, and the up- 



' Kiug: Op. cit., p. 455. 



-This occurrence is referred to by Professor Whitney, who Jiscovered uo fossils in it (Auriferous 

 Gravels, p. 23). 

 ' See page 64 . 



