86 WARREN DUPRE SMITH AND EARL L. PACKARD 



the California boundary, which have been correlated with Hersh- 

 ey's/ Abrams, and Salmon series, it may be permissible to quote the 

 description of the typical fades of those rocks as applicable in 

 general to the Oregon beds: 



It [the Abrams mica schist] is composed of thin folia of muscovite of dull 

 colors .... separated by irregular layers of white quartz representing the 

 original laminae. Throughout it is very highly siliceous, and doubtless por- 

 tions of it would by some be called micaceous quartz schist. In certain belts 

 the silica predominates to such an extent as to cause it to outcrop hke great 

 veins of very glassy white and dark blue quartz. 



This mica schist in California appears to grade upward through a 

 graphite and actinolite schist to the hornblende schist series. These 

 mica and hornblende schist series have an estimated thickness of 

 i,ooo feet, which is no more than that developed by the first men- 

 tioned in the upper Coffee Creek section of northern California. 



These old schists are in contact with the tonalite batholith at 

 the California-Oregon boundary south of Ashland. This intrusive 

 is of a much later date and possibly has been the dominant factor 

 in the alteration of these sedimentary rocks to their present con- 

 dition. Winchell states that these old beds are so intimately 

 associated with intrusives as to make stratigraphic studies impos- 

 sible in the vicinity of Red Mountain. The schistosity parallels 

 the structure of the adjoining Paleozoic rocks, which have a general 

 northeasterly strike. 



Since these rocks, which were presumably originally argillaceous 

 sandstones, or in places carbonaceous, as is testified by the graphitic 

 schists, have been so completely metamorphosed their geologic 

 age must be determined solely upon physical bases. The consensus 

 of opinion seems to be that the schists at the state line are to be 

 correlated with the Abrams and Salmon schist series of supposed 

 Algonkian age. 



PALEOZOIC 



Devonian-Carboniferous. — During a part at least of the Paleozoic 

 a sea covered a portion of eastern and southwestern Oregon. 

 Although the Paleozoic rocks outcrop in both sections, the forma- 



^ O. Hershey, Am. GeoL, XXVII, 227. 



