0, H. Hershey — Cretaceous Outliers in California. 33 



Art. YIII — The Significance of Certain Cretaceous Outliers 

 in the Klamath Region^ California ; by Oscar H. Hershey. 



Cretaceous remnants occur in the southern part of Trinity 

 County, California, in five very limited areas. They are dis- 

 tinguished from the IN'eocene deposits by their better lithifica- 

 tion, by the gravel being almost exclusively of qu:.rtz and 

 displaying the marine type of rounding, by their occupyiug 

 structural basins and not valleys of erosion, and by their being 

 identical lithologically with the Cretaceous deposits in the 

 neighboring portion of the Sacramento Yalley. 



The principal Cretaceous outlier is in the valleys of Indian, 

 Hedding and Brown's Creeks, a few miles northwest of Bully 

 Choop peak. It is about three square miles in area, and elon- 

 gated in a direction west-southwest. It consists of several 

 hundred feet of fine, well-stratified, yellowish sandstone and a 

 little of the olive-colored shale so characteristic of the Upper 

 Cretaceous in the Sacramento Yalley. It rests unconformably 

 on the Abrams mica schist. 



The next area is at the junction of the IS'orth Fork of the 

 East Fork of Hay Fork with the main East Fork Creek. It 

 occupies less than a square mile in area, but dips distinctly 

 toward the center of the small basin. The lower bed is a 

 coarse, mixed breccia and conglomerate. The angular frag- 

 ments were derived from the underlying Paleozoic slates and 

 cherts. This bed differs from the usual basal conglomerate of 

 the Cretaceous in the Sacramento Yalley, but its identification 

 is made certain by its being overlaid by the olive-colored 

 shales, whose characters are unmistakable. 



The third area occurs on the divide between Hay Fork and 

 Salt Creeks, at the head of Dobbin Gulch. There is about a 

 thousand feet of coarse conglomerates with some green sand- 

 stone, yet the deposit is only about one square mile in extent. 

 On all sides it dips distinctly toward the center of the basin at 

 angles between 20" and 30°. It rests on Paleozoic slates and 

 cherts, the Clear Creek volcanic series and the Bragdon slate, 

 the latter of very late Jurassic age. The pebbles, cobbles and 

 occasional bowlders which compose the rock are, however, 

 chiefly" of white, yellow, brown, pink, blue and black quartz, 

 derived from the rocks of the Klamath region but at some dis- 

 tance from their present position. 



The fourth remnant occurs at the junction between Pattle- 

 snake and Post Creeks and is about one and one-half square 

 miles in area. It rests on the Clear Creek volcanic series, and 



Am. Jour. Sci.— Fourth Series, Vol. XIY, No. 79.— July, 1902. 

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