BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



VOL. 1, PP. 411-442, PLS. 6-8 APRIL 21, 1889 



SANDSTONE DIKES. 



BY J. 8. DILLER. 

 {Read before the Society December 28, 1890.) 



CONTENTS. 



Page. 

 Introduction 411 



Distribution of the Sandstone Dikes in Northern California 412 



General Kelations 412 



Dikes on the North Fork 414 



Dikes on Crow Creek 415 



Dike on Squaw Creek 416 



Dikes on Roaring River 416 



Dikes of Poverty Gulch 418 



Dikes of Aiken Gulch (Camp Creek) 418 



Dikes on Middle Fork 418 



Dikes on Dry Creek 420 



Dikes of Fight Gulch 42^ 



Dikes on Salt Creek, etc 423 



General Description 424 



Mineralogical Composition and Minute Structure 425 



Some associated Cretaceous Sandstone Beds 428 



Chemical Composition of the Sandstone Dikes and Beds 429 



Geologic Relations and Origin of the Sandstone Dikes 430 



Position and Age 430 



The Dikes occupy Joint Fissures 431 



Method of filling the Fissures 432 



Phenomena commonly associated with Earthquakes 435 



The Region is favorable for the Production of such Phenomena 436 



Source of the Sand in the Dikes 436 



Origin of the Joints in the Dikes 437 



Distribution of the Dikes, considered as Earthquake Phenomena 437 



Crosby's Theory of the Origin of parallel Joints 438 



Sandstone Dikes observed in other Localities 439 



Summary 441 



Discussion 442 



Introduction. 



Several years ago, while studying the Cretaceous shales upon the northwest- 

 ern border of Sacramento valley in California, I observed in a stream bed 

 a number of large fragments of sandstone. They were carefully examined 

 LIV— Bull. Gf.ot.. Soc. Am., Vol. 1, 1889. (41 1 ) 



