UNIVERSITY OF CALIFORNIA 



Bulletin of the Department of Geology 



Vol. 2, No. 10, pp. 315-326, PI. 9. ANDREW C. LAWSON, Editor 



M IN ERA LOGICAL NOTES. 



BY 



Arthur S. Eakle. 

 WITH CHEMICAL ANALYSES, BY W. T. SCHALLER. 



CONTENTS. 



PAGE. 



I. Pectolite, Datolite, and Other Minerals occurring near Fort Point, 



San Francisco, Cal 315 



Pectolite 316 



Datolite 317 



II. Zircon Crystals from Siskiyou County, California 319 



III. Esmeraldaite, a New Hydrous Sesquioxide of Iron, from Esmeralda 



County, Nevada 320 



IV. Coquimbite, from the Redington Mine, Knoxville, Cal 322 



V. Altaite Crystals, from Sawmill Flat, Tuolumne County, Cal 324 



I. PECTOLITE, DATOLITE, AND OTHER MINERALS OCCURRING NEAR 

 FORT POINT, SAN FRANCISCO. 



The coast rock on the southern shore of the Golden Gate, 

 extending for some distance on both sides of Fort Point, consists of 

 serpentine, which represents the northern outcrop of the great 

 serpentine laccolith, extending across the city of San Francisco, 

 intrusive in the Franciscan sandstones. This mass of serpentine 

 has been described by Palache,*and classified by him as a lherzo- 

 lite-serpentine. Numerous boulders of serpentine are strewn along 

 the beach west of the fort, which show manifold varietal differences 

 in color and structure, and contain abundant veins of secondary 



*"The Lherzolite-serpentine and Associated Rocks of the Potrero, San 

 Francisco," this Bulletin, 1894, Vol. 1, pp. 161-192. 



