506 DEPARTMENT OF TEE INTERIOR 



2 GEORGE V., A. 1912 



They may have been intruded during the Eocene, Oligocene, or early Miocene, 

 preferably during the Miocene; in any case they seem to antedate the Castle 

 Peak stock. 



The following table indicates the probable correlations for the Hozomeen 

 range : — 



Pleistocene Glacial and Recent deposits. 



„. f Syenite-porphyry chonolith. 



miocme { Castle Peak granodiorite stock. 



Miocene '' f Li g htnin £ Creek diorite stocks. 



' * \. Porphyrite sills and dikes cutting Pasayten series. 



Cretaceous ( Shasta- Chico) . . .Pasayten series, members B to L. 



Cretaceous, near or at base of 

 Shasta group Pasayten volcanic formation, agglomerate beds and volcanic neck (?) 



Unconformity. 



Jurassic s Remmel granodiorite batholith. 



Carboniferous (Cache Creek) Hozomeen series, quartzite, chert, limestone, and dominant greenstone. 



SUMMARY OF GEOLOGICAL. HISTORY. 



The Hozomeen formation represents a part of the Paleozoic formation 

 which was intensely mashed and metamorphosed in Mesozoic, doubtless Jurassic, 

 time. That crustal revolution was immediately followed by the invasion 

 of the Remmel batholith from below. Rapid erosion followed, during which the 

 cover of the batholith was partly removed. The region subsided just after the 

 erosion-surface had been deeply covered by the mantle of Pasayten pyroclastics. 

 The subsidence continued during the formation of a typical geosynclinal 

 depression. Keeping pace with the sinking, an enormous thickness of (partly 

 marine) Cretaceous strata was piled on the geosynclinal surface. This 

 great body of strata was deformed in post-Cretaceous time and, on account 

 of the intensity of the action, it seems best to attribute this upturning 

 to the well-established post-Laramie, early Eocene orogenic revolution. The 

 penetration of the Cretaceous beds by porphyrite sills and dikes, by diorite 

 stock-like masses and by the Castle Peak stocks with its satellites, probably 

 all occurred in later Tertiary time, with the Miocene assumed as the best date 

 for the largest stock. The great faults about Mt. Hozomeen may date from the 

 early Eocene or from a later, pre-Pliocene time. The possibility is thus recog- 

 nized that they may be somewhat younger than the folds in the upper strata 

 of the Pasayten series. 



