PETROLOGICAL ABSTRACTS AND REVIEWS 473 
Watson, THomAs L., and CLinE, Justus H. “Petrology of a 
Series of Igneous Dikes in Central Western Virginia,” Bull. 
Geol. Soc. Amer., XXIV (1913), 301-34, pls. 3, figs. 5, analyses. 
Describes a series of dikes occurring in Rockbridge, Augusta, Rock- 
ingham, and Highland counties, Virginia. The rocks are diabase, 
granite-felsophyre, quartz-gabbro, nephelite-syenite, teschenite, and 
camptonite. All the rocks are analyzed and their positions in the 
C.I.P.W. system are determined. 
Watson, THomas L., and TABER, STEPHEN. “Geology of the 
Titanium and Apatite Deposits of Virginia.” Bull. III-A, 
Vargo Gah. (SOs, TOUR, IAD. BelieOlSs By, Wess QA, 7 oon 
bibliography on titanium. 
After a general discussion of the titanium minerals and a brief 
description (28 pp.) of the rutile deposits of the world, the geology of the 
ore deposits in the Amherst-Nelson region is given. The rocks are 
described in detail, and chemical analyses of some of the associated 
rocks—biotite-quartz-monzonite-gneiss, syenite, gabbro, nelsonite, and 
diabase—are given. In the first the plagioclase is oligoclase, Ab2An;; 
the second rock is really an andesinite, or andesine-anorthosite as used 
-by the authors; the rock described as gabbro consists chiefly of andesine 
and hypersthene with ilmenite, apatite, orthoclase, quartz, biotite, etc.; 
the nelsonite is a dike-rock consisting essentially of ilmenite and apatite. 
Wuerry, Epcar T. “A Peculiar Oolite from Bethlehem, Pennsyl- 
vania, Proc. U.S. National Mus., XLIX (10915), 153-56, pls. 2. 
Describes an oolite in which the ooids show a ‘‘half-moon”’ effect, the 
upper portions being light and the lower dark. An explanation for this 
peculiar character is given. 
WHERRY, EpGAR T., and GorDON, SAMUEL G. “An Arrangement 
of Minerals According to Their Occurrence,’ Proc. Acad. 
Nat. Sct., Philadelphia, 1915, 426-57. 
Minerals are classified according to their occurrence in igneous rocks, 
pegmatites, hydrothermal deposits, fumerolic deposits, or sediments. 
Each of these main divisions is subdivided into various groups, and under 
each is given a list of the minerals which occur. It is a very useful list. 
