14 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



of the slates and jaspers of the Franciscan series. The 

 true relations of these slates to the Devonian rocks in the 

 vicinity of Gazelle, in the same county, are not definitely 

 known, though probably they include the strata of the 

 Scott River Valley, referred to by Diller and Schuchert 

 (1894) as probably Triassic. 



In Southern Oregon the basement rocks are largely simi- 

 lar. Occasionally granitic rocks form the floor for Creta- 

 ceous sediments, as at Ashland, Oregon, in the vicinity of 

 Horsetown, and on some of the tributaries of the Cotton- 

 wood Creek, Shasta County, and a stream of the same 

 name in Siskiyou County, — California. But generally 

 upon either margin of the Cretaceous basin there are found 

 the folded and eroded older sediments. Thus both the 

 situation and the distribution of the Cretaceous deposits 

 are suggestive as to their period of folding; but the 

 evidence is far from resting here. There are facts of 

 erosion in the Klamath Mountains that furnish confirmatory 

 evidence. 



2. The Sacramento Valley. 



The Shasta-Chico series, as represented in the upper 

 Sacramento Valley, where it has been described by Diller, 

 and afterward by Diller and Stanton, is said to consist of 

 about thirty thousand feet of strata in which the sediments 

 vary from conglomerates to sandstones and clay shales. 

 The lower nineteen thousand nine hundred feet of the 

 section along Elder Creek, Tehama County, is composed 

 chiefly of shales with a subordinate amount of sandstone 

 and of conglomerates, often of only local occurrence. 

 Higher in the section, sandstones become more abundant, 

 until at twenty-six thousand feet they give place to massive 

 conglomerates and sandstones. The whole series has a 

 varying dip to the eastward or southeastward, being near 

 the base often nearly vertical, but generally not exceeding 

 an inclination of thirty degrees. Toward the top it is 

 sometimes but little disturbed. 



