380 The Affiericaji Geologist. December, i898 
Solosbergytc and Tinguayte from Essex County, Mass. By Henry 
S. Washington. {Am. J. Sci.,1^6, 176-187.) 
The solosbergytc forms a dike four feet wide cutting granite, and 
IS specially distinguished by the presence of glaucophane and riebeck- 
ite. One complete analysis is given and compared with four analyses 
from other regions; and from the analysis the mineral composition is 
computed, the chief constituents, in order of abundance, being, — albite, 
orthoclase, glaucophane, riebeckite, quartz and titanite. In this con- 
nection an analysis is also given of the Quincy granite in which T. G. 
V-yhitc had reported a blue hornblende which he referred to glauco- 
phane; analyses of four foreign granites are quoted for comparison; 
and the calculation of the mineral composition gives, in order of 
abundance, quartz, albite, orthoclase, riebeckite and glaucophane, the 
riebeckite largely predominating over the glaucophane. The analyses 
are of special interest as pointing to the existence of a purely iron- 
alumina glaucophane. 
The tinguayte also occurs as a dike in the granite; and its most 
notable characteristic is the occurrence in it, apparently as an original 
constituent, of a large proportion (37.4 per cent.) of analcite. As 
before, the analysis is compared with the similar rocks of other re- 
gions and the mineral composition is deduced therefrom. w. o. c. 
Distribution and (2uantitative Occurrence of Vanadium and Molyb- 
denu7n in Rocks of the United States. By W. F. Hillebkand. {Am. 
f. Sci., ij6, 2og-2i6.) 
The analytic data show the quantitative occurrence and distribution 
of vanadium in a large number (57) and variety of igneous rocks, in a 
few of the component minerals of these rocks, and in a few metamor- 
phic and secondary rocks. Two of the samples in the last series were 
highly composite, one representing 253 sandstones and the other 498 
limestones. The conclusions shown by a comparison of these data 
are: that vanadium occurs in quite appreciable amounts in the more 
basic igneous and metamorphic rocks, up to .08 per cent, or more, 
of V2O3, but seems to be absent or nearly so from the highly siliceous 
ones; that the chief source of the vanadium is the heavy ferric-alumin- 
ous silicates — the bioiites, pyroxenes, amphiboles; that limestone and 
sandstones contain only very small amounts of vanadium; that molyb- 
denum is confined to the more siliceous rocks; and so far has been 
found only in traces in these. w. o. c. 
An Occurrence of Dunyte in Western Massachusetts. ByG. C. Mar- 
tin. {Am. J. Sci., 1^6, 244-248.) 
The dunyte or olivine rock, of which only two other occurrences 
are known in North America, forms an irregularly elliptical boss of 
distinctly igneous origin, about 1,000 by 2,000 feet in extent, in the 
town of Cheshire. The olivine is extensively serpentinized, and the 
original accessories include chromite, magnetite and picotite. The 
olivine, purified by the Thoulet solution, gave on analysis: MgO, 
51.41; Si02, 40.07; FeO, 4.84; AljOs, 1.94; HgO, 1.03; total, 99.29. 
w. o. c. 
