2r2 (>. II. Hershey — Belt and P dona Series. 



math region on the west, but resembling the Lower Cambrian 

 and Belt quartzite-slate series of Nevada, and the quartzites 

 and slates of the Oro Grande series in Southeastern California. 

 With it is a granite, probably intruded in the quartzite. 



In the Klamath region the Devonian rocks, including much 

 igneous material, rest nonconformably on a series of crystalline 

 schists that have been described by me under the names of the 

 Abrams mica schist and Salmon hornblende schist.* In the 

 summer of 1907 I greatly extended my acquaintance with this 

 series. I found the hornblende schist member (which also con- 

 tains fine-grained hornblende and micaceous gneisses) exposed 

 in a narrow belt along Chinech Creek southeast of Orleans, and 

 at Elk Creek near Happy Camp in Siskiyou County ; in the 

 latter area it attains a maximum width of several miles, with a 

 prevailing eastern dip and an exposed maximum thickness of 

 at least 5,000 feet. Near Seiad post-office there is an acid, 

 white, pegmatitic granite, apparently very old (probably Arch- 

 ean), abounding in large inclusions of hornblende schist and 

 gneiss from the Salmon (Chinech) formation, but chiefly a fine- 

 grained, thin-bedded, hard, vitreous quartzite of pink, white, 

 and light green colors, with some mica schist and traces of 

 marble. The quartzites seemed to represent a formation not 

 heretofore discriminated in the Klamath region. It may 

 extend south to Marble Mountain. 



Farther up the Klamath River is another belt of Archean 

 schists. Under the Salmon hornblende schist, much of it 

 rather coarse-textured, there is about 2,000 feet thickness of 

 dark gray mica schists of the Abrams formation. Under this 

 is 1,000 feet of light greenish (chloritic and, in places, actino- 

 litic) coarse-textured mica schist, part of which appears to 

 have originally been a granite, and somewhat resembles the 

 lower member of the Pelona schists of Los Angeles County, 

 California. f It is my impression that the various phases of 

 schists do not maintain a regular sequence throughout the area 

 of development of the Abrams formation. The chloritic and 

 actinolitic schists probably represent igneous rock intruded at 

 various horizons in the original sediments. By following the 

 old Kelsey trail to Marble Mountain, I crossed the mica schist, 

 then probably 5,000 feet of hornblende schist and hornblende 

 gneiss, then intrusive granite and basic rocks, then fine-textured 

 mica schists and micaceous and hornblendic gneisses accom- 

 panied by tbe peculiar, thin-bedded, white quartzite and white 

 marble of the Seiad area. Higher there is a great series of 



* Metamorphic Formations of Northwestern California; Am. Geol., vol. 

 xxvii, pp. 225-245, 1901. 



fSome Crystalline Eocks of Southern California; Am. Geol., vol. xxix, 

 1902. 



