354 RULIFF S. HOLWAY 



San Jose. — The hills just south of the Oak Hill Cemetery are 

 composed largely of masses of peridotite and gabbro with the resulting 

 serpentine. On one slope there is an outcrop of grayish-green rock 

 that is in part eclogite. The garnets are small and sometimes form 

 veins of the compact granular variety of this mineral. In the slide 

 there is much glaucophane and chlorite, the latter frequently exhibit- 

 ing the Prussian blue interference color. A few crystals of feldspar are 

 found, and also considerable mica and sphene. The outcrop is of 

 interest mainly because of its occurrence in an area of igneous rocks. 



Edogites from other localities. — Slides and hand specimens from 

 Sonoma county have been studied in the laboratory. They are of the 

 glaucophane type of eclogite and have the usual accessories. Nutter 

 and Barber' state that the eclogite occurs in large masses associated 

 with schists. Melville^ describes a bluish glaucophane schist from 

 Mount Diablo with streaks of green and with innumerable garnets. 

 No slide or hand specimen has been available. Among the rocks of 

 Catalina Island, W. S. T. Smith^ describes a garnet amphibole of 

 greenish or brownish hornblende and carrying roughly rounded gar- 

 nets. Rutile is mentioned as an inclusion. The term "eclogite" is 

 not used in his account. A specimen of eclogite from Anacapa 

 Island, some sixty miles to the northwest of Catalina, is in the Law 

 collection, but there is no note as to its occurrence. 



OREGON ECLOGITE. 



Although the locality is outside of California, fuller reference 

 should be made to the rocks described by Diller from Port Orford. 

 He finds glaucophane-, actinolite-, mica-, and epidote-schists all grad- 

 ing into each other and all having the same origin. Garnets are 

 sometimes found in abundance. These schists he thinks are derived 

 from rocks of the basaltic type. In many places the original rock is 

 changed to plagioclase hornblende rock. Usually the pyroxene 

 alters to a green hornblende, but sometimes to a blue — giving the 



I Op. cit., p. 740. 



^ "Notes on the Chemistry of the Mount Diablo Rocks," Bulletin of the Geological 

 Society of America, Vol. II, p. 403. 



3 "The Geology of Catalina Island," Proceedings of the Californiu Academy of 

 Science, Geology, 3d ser., Vol. I, p. 62. 



