572 The American Naturalist. [June, 
MINERALOGY AND PETROGRAPHY! 
Mineralogical News.—The long expected monograph by Brég- 
ger? on the minerals of the syenite-pegmatite veins of the augite syen- 
ite and nepheline syenite region of Southern Norway has at last made 
its appearance. The special part of the volume, which describes in 
great detail seventy mineral species, is prefixed by an introduction of 
235 pages, in which the geology of the region is discussed and the 
eruptive nature of the pegmatite veins is proved. An abstract of this 
portion of the work will be given in another place. Of the seventy 
mineral species recognized in the veins five are of sulphides, one isa 
sulpho-salt, three are oxides, three are hydroxides, one is a haloid 
compound, one a ferrate, two are borates, two phosphates, two are 
members of the zircon group, three belong to the epidote group, two 
to the group of the datholites, three to the garnets, three to the micas, 
two to the nepheline group, two to the leucophanes, seven to the 
pyroxenes, four to the hornblendes, four are members of the melanocer- 
ite group, three are feldspars, seven are zeolites, and nine others are 
various silicates. The only carbonate detected, beside two fluo-car- 
bonates, is calcite. It is evidently impossible to mention even all of the 
important discoveries made by the author in his studies of the wonder- 
ful suite of specimens collected by him. We can only refer briefly to 
the most important of them. Measurements of “illingite yielded a: b: 
c=6689 : 1: 1.2331. Tabular crystals of hydrargillite gavea: b: c 
=1.7089 : 1: 1.9184; A=85° 20’ 10”. These are occasionally un- 
twinned, but more frequently twinned forms are found in which the 
twinning planes are oP (corresponding to DesCloizeaux twins par. 
æ Pcs), co Pcs (occasionally), ts Pz (?), and oP; and a fifth form in 
which the twinning plane is perpendicular to oP, Optically, plates of 
the mineral act uniaxially. Xenotime, while containing many elements, 
yielded upon analysis figures that may be reduced to correspond to 
the formula Y, (PO, 2 An examination of thin sections of orthite (allan- 
SiO, ALO, FeO, CeO, BO, FeO CaO NaO H,O 
31.83 2.72 88 -24 16.51 16.74 29.54 75 -79 
‘Edited by Dr. W. S. Bayley, Colby University, Waterville, Me. 
* Zeits. f. Krystall., XVI. Specialler Theil, 664 pp., XXVII. Pl, 
