344 Diller — Klamath Mountain Section, California. 



sides is to the northeastward and the fissile structure of the 

 schists, although greatly crumpled, is for the most part in the 

 same direction, suggesting that the quartz epidote schist upon 

 the southwest side may be older than the sericite schist. 



Wortkeasti rn belt of schists. — The northeastern belt of schists 

 was seen only in the drainage of Salmon River and along 

 Browns Creek near Douglass City on Trinity River. Although 

 in general character the sericite schist of Brown Creek is like 

 that of South Fork Mountain, its associations are quite different. 

 On the west side it is limited by the belt of sediments, contain- 

 ing the Hall City limestone, which is Carboniferous, and upon 

 the east occurs a mass of schistose hornblende rocks apparently 

 of igneous origin. 



The South Fork Mountain belt of sericite schist is in gen- 

 eral quite regular in outline and free from igneous masses, but 

 the northeastern belt in Bully Choop and Salmon Mountains is 

 much broken by a great variety of igneous intrusions. 



Devonian. 



Southwestern Devonian belt. — In the southwestern belt 

 there is a line of Devonian limestone lentils* which may be 

 traced with many interruptions for over 100 miles parallel with 

 the South Fork of Trinity River from its source to near Hoopa 

 Valley, and throughout the whole distance the limestone 

 rarely gets over a mile or two away from the contact with the 

 schist of South Fork Mountain. It is probable that the same 

 limestone occurs on the western slope of the Sacramento Val- 

 ley at the Basin about 30 miles west of Red Bluff, where 

 traces of crinoids, corals and other doubtful forms were found 

 (1887) in one of a group of limestone ledges. 



The first locality in this belt visited last summer was White 

 Rock near the head of the South Fork of Trinity River, a few 

 miles northwest of North Yallo Bally Mountain. The lime- 

 stone is intimately associated with and broken by igneous 

 rocks, some of which .are vesicular as of surface flows. The 

 caverned mass of limestone, which is scarcely an eighth of a 

 mile in length, has tumbled down the slope, forming prominent 

 cliffs and talus for nearly 1,000 feet. It is rather crystalline 

 and the few fossils obtained were numbered 704. 



Northwest from White Rock, within three-fourths of a mile, 

 several small lenses of limestone crop out, and from one of 

 these, only three feet in greatest extent, a number of shells and 

 coiled forms were obtained and numbered 705. Concerning 

 these fossils, Mr. Charles Schuchert of the U. S. National 

 Museum at Washington, D. C, reports as follows : 



* Judging from the earlier collections, this belt of limestone was doubt- 

 fully referred to the Jura-trias, U. S. Geol. Survey Bull. 196, p. 64. 



