Mineralogy and Petrograplty. 
mplet 
He di 
lete catalogue of the 
" ides them into (1) 
crystallized minerals occurring in pieces of foreign rock cast up during 
the eruptions of Monte Somma and the earlier eruptions of Vesuvius; 
(2) those forming lava bombs ; (3) those occurring in the Monte Som- 
ma conglomerate, as a result of contact action ; (4) those produced in 
the fumaroles by sublimation ; (5) those formed in the lava during 
its cooling ; and (6) those present on the walls of the amygdaloidal 
cavities in the lava. One hundred and twenty five mineral species 
are briefly described, and the name of the writer first mentioning 
them is given. The catalogue will prove of great convenience to 
collectors in the region and to those in charge of collections embrac- 
ing many Vesuvian specimens.— Brezina ^ would add tellurite to the 
group comprising the oxides claudetite and valentinite. Crystals 
obtained from a porous sandstone at Facebaja were measured and 
found to be orthorhombic with a : b : c = .4566 : 1 : .4693. 'J^he 
predominant faces are oo P^, qd Pg-, cxs P^, oo P and P, and the 
plane of the optical axes is oo P~.— In tlie limestone near Bagneres 
de Bigorre, France, are little crystals of black albite, which, accord- 
ing to Lacroix,^ have the following composition : 
■SiOs AlgOg Na^O CaO Ign Specific gravity 
67.04 20.45 10.57 .65 1.80 2 563 
— -Limur ■* describes a staurolite crystal from Moustoir-Ac, Morbi- 
han, France, which consists of a core, composed of quartz and 
staurolite material, surrounded by two zones of staurolite, one with 
a granular structure, and the other with a fibrous structure, due to 
the arrangement of little needles perpendicular to the prismatic 
faces of the crystal. 
' Rock-Forming Minerals." ^ — This 
— excellent book for beginners in the 
study of microscopical geologv. It includes an introduction to the 
methods made use of in the investigation of the optical and other 
physical properties of minerals, discusses the the-ry of polarized 
light explains what is meant by *' optical axes," ''bisectrices,^' 
double refraction, etc., describes the polarizing microscope and other 
instruments used in the examination of minerals, and gives the 
principal characteristics of those minerals which enter into the com- 
position of rocks. The explanations of the phenomena presented 
by sections of minerals when observed in polarized light, are given 
' Neues Jahrb. f. Min., etc.. 1888 ii.. t>. 123 ' 
^Ref.N.J. B., 1888, i., p.206. ' 
4 fu • ?*^^- ^^^^^' de Min., xi., p. 64. 
rru Ko^k-Forming Minerals. By Frank Rutley. With 126 ills/and 252 pp 
Thos. Murby, 3 Ludgate CircusjBuildings, London, 1888. 
