BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 2, pp. 383-414, PL. 15. MARCH 30, 1f91 



THE GEOLOGY OF MOUNT DIABLO, CALIFORNIA. 



BY H. W. TURNER. 

 WITH A SUPPLEMENT ON 



THE CHEMISTRY OF THE MOUNT DIABLO ROCKS. 

 BY W. H. MELVILLE. 



{Read before the Society December 31, 1890.) 



CONTENTS. 



Page. 



General Remarks 384 



The Metamorphic Area 384 



The Pre-Tertiary Igneous Rocks _. 385 



Diabase 385 



Peridotite and Pyroxenite 388 



Gabbro i 391 



Mineral Deposits 391 



Precious Metals, etc 391 



Coal 392 



Mineral Springs 392 



Tertiary Eruptives 393 



The Sedimentary Terranes 393 



The General Section 393 



The Knoxville Beds 394 



The Chico Beds 395 



The Tejon Beds 395 



Miocene Beds 396 



Pliocene Beds 396 



Post-Pliocene Beds 399 



The Epoch of Upheaval 399 



Notes on the Chemistry of the Mount Diablo Rocks 403 



Introductory Note 403 



Series I ; Shales and Gabbros from Bagley Canon ^ 403 



^Series II; Specimens from near Bagley Creek 405 



Series III ; Specimens from Arroyo del Cerro 407 



Series IV ; Specimens from near Arroyo del Cerro 408 



Series V ; Shales from the Head of Bagley Creek 410 



Series VI ; Tertiary and Cretaceous Sandstones 411 



Series VII ; Diabase from Mitchell Canon 412 



Glaucophane Schist 413 



Peculiar Serpentine 413 



LVII— Bull. Geol. Soc. Am., Vol. 2, 1890. (383) 



