698 The American Naturalist. [August, 
Haute-Loire, France, contain many interesting minerals, short descrip- 
tions of which are given by Lacroix.’ In those from the first-named 
locality are vitreous orthoclase, anorthite microperthite, zircon in bril- 
liant, transparent, wine-red and in colorless or brown and light ruse 
erystals, sphene, apatite, corundum and biotite. The last named min- 
eral is an original component of the rock yielding the bomb, while the 
zircon, sphene and apatite are certainly new products. The Monac 
sanidinites differ from those of Menet principally in being saturated 
with secondary substances. 
Igneous Rocks from Montana.—Among the rocks found in the 
mountains of Montana and described by Lindgren’ are dacite, trachytes, 
basalts and augite-syenites. One variety of basalt consists of fresh 
olivine, augite and analcite in a groundmass composed of magnetite, 
apatite andanalcites of a second generation. The rock was described 
in one of the Tenth Census Reports, where the analcite was stated to be 
in all probability an alteration product of nosean. The author now 
regards the mineral as unquestionably original. 
Petrographical News.—Mr. Cole’ describes a section of devitri- 
fied perlitic obsidian from Rocche Rosse, Lipari, in which the rock is 
much shattered. Around the fragments of glass thus formed spheru- 
litic substance has resulted from the devitrification of their material. 
Beginning at the cracks separating the fragments the devitrification 
has progressed inward until a spherulitic zone now surrounds 
each piece of glass——The mica schist around the granite 0 
the Schneekoppe in the Riesengebirge, Silesia, has heen changed by the 
eruptive from a muscovite-garnet-quartz-schist to a schistose aggregate 
of quartz, muscovite, biotite, andalusite, and new, blood-red garnets. 
The biotite is in isolated small plates that are quite different in char- 
acter from the flakes of muscovite adhering to the quartz grains in the 
original rock. A few augite, saussurite and quartz diorites, a gabbro 
and several porphyries, porphyrites and diabases from the hills sur- 
rounding the Muir Glacier, in Alaska, are briefly described by Will- 
iams’ in an appendix to Reid’s account of the glacier. In the oli- 
vine diabase of a dyke cutting the Sioux quartzite, in Minnehaha Co., 
Bull. Soc. Min. d. Fr., xiv, 1892, p. 314. 
®Proc. Cal. Acad. Sci., 2, vol. iii, p. 39. 
TMineralogical Magazine, ix, p. 272. 
*Zeits. d. Deutsch. Geol. Ges. xliii, 1891, p. 730. 
Nat. Geog. Mag., Washington, iv, p. 63. 
