Geology and Mineralogy. 73 



earthy material consisting of a siliceous limonite. The black 

 mineral has a vitreous luster and is translucent in thin edges ; it 

 is brittle, with conchoidal fracture and gives a yellowish brown 

 streak. The hardness is 2*5 and specific gravity 2*578. An 

 analysis by W. T. Schaller gave : 



Fe 3 3 H 2 O(110°) H 2 A1 2 3 CaO P 2 5 Si0 2 Organic 



(over 110°) 



56-14 15-94 10-24 5*77 3*35 4'49 2'05 1-37 = 99*35 



If all the substances shown in the analysis, except the Fe 2 3 

 and H 2 0, are considered as impurities, the percentage composition 

 becomes: Fe 2 3 68-20, H 2 31-80=100. This corresponds to 

 Fe 2 3 -4H 2 0.— Univ. Calif., Bull Geol., ii, 315, 1901. 



9. Mineralogy of California. — Recent issues in the series of 

 the Bulletin of the Department of Geology of the University of 

 California (vol. ii, pp. 315-320 and 327-348) contain contributions 

 to the mineralogy of the State. A. S. Eakle describes fine crys- 

 tals of datolite, also pectolite occurring in veins of the serpentine of 

 Fort Point, San Francisco ; analyses by W. T. Schaller are added. 

 The same author describes the new hydrated iron sesquioxide, 

 esmeraldaite (see p. 72) ; the occurrence of coquimbite at the 

 Redington mine, near Knoxville ; also crystals of the lead tellu- 

 ride, altaite, with the forms a (100), o(lll), /3(332) from Sawmill 

 Flat, Tuolumne County. 



W. C. Blasdale shows that the green amphibole of the Coast 

 Range in the neighborhood of Berkeley agrees with actinolite in 

 physical characters though somewhat peculiar in chemical 

 composition, alkalies being present to the amount of 2^- per cent. 

 A blue amphibole from the same region comes very near to 

 glaucophane but differs rather widely from the crossite of 

 Palache. Descriptions are also given of tremolite, chlorite, talc 

 and other species. 



The Mesa Grande Mountains in San Diego County have recently 

 yielded beautiful crystals of red and green tourmaline, occurring 

 in lepidolite and in the associated quartzite. The crystals are 

 often well terminated and many of them are of considerable size, 

 transparent and of great beauty. The variety rubellite is most 

 common, but many specimens show the characteristic zonal 

 arrangement of color both concentric and in horizontal bands. 

 (See further remarks by Kunz on the Production of Precious 

 Stones in Min. Resources of the U. S. for 1900.) 



10. New localities of Nephrite. — A recently issued inaugural 

 dissertation, by A. Dieseldorff, describes a series of rocks and 

 fossils from Chatham island, as also from D'Urville and Stephens 

 islands, New Zealand. Among other results, the author has 

 made the interesting observation that nephrite occurs in place 

 in serpentine as the mother rock on D'Urville island. This, as 

 he notes, is the first time that nephrite has been definitely located, 

 although obtained so frequently from New Zealand. The 

 nephrite nodules occurring in the serpentine' show uralitization, 



