662 - The American Naturalist. [August, 
52°-56° and in the phonolitic type, the most acid variety, it is 50°- 
53°. In each of the types labradorite and sometimes oligoclase phen- 
ocrysts are common, but the feldspar of the groundmass differs in 
character in the different types. In the andesitic type it is oligoclase, 
in the leucite variety andesine, and in the phonolitic type sanidine. 
A Nepheline-Syenite Bowlder from Ohio.—Miss Bascom‘ 
has found in the drift near Columbus, Ohio, a bowlder which consists 
of nepheline-syenite porphyry. The rock is composed of large pheno- 
crysts of oligoclase and smaller ones of nepheline, augite, hornblende 
and olivine in a groundmass composed of plagioclase and orthoclase 
laths, hornblende, biotite, augite and magnetite in a feldspathic mat- 
rix. 
Crystalline Rocks of New Jersey.—In a report on the Arch- 
ean Highlands of New Jersey, Westgate’ states that the northern half 
of Jenny Jump Mt., Warren Co., consists mainly of gneisses with a 
small area of crystalline limestone, diorites, gneisses, etc. The gneisses 
are granitoid biotite-hornblende varieties, biotite-gneisses and horn- 
blende-pyroxene gneisses. In the first named variety the prevailing 
feldspars are microcline and microperthite, and in the pyroxene gneisses 
plagioclase and orthoclase. The gneisses are cut by pegmatite dykes, 
amphibolites and diabases. 
Associated with the white crystalline limestones are fibrolite and bio- 
tite gneisses, hornblendic gneiss, amphibolites, gabbros, norites and 
diorites, most of the latter of which show evidence of an eruptive origin. 
Another type of rock often found associated with the limestones is a 
quartz-pyroxene aggregate, in which the pyroxene is a green or white 
monoclinic augite. The limestone, the fibrolite and biotite gneisses and 
the quartz-pyroxene rock are thought to be metamorphosed sediments. 
Simple Crystalline Rocks from India and Australia.—Judd* 
gives us an account of several simple crystalline rocks from India and 
Australia. One is a corundum rock composed principally of corundum 
grains with rutile, picotite, diaspore and fuchsite as accessory consti- 
tuents. The corundum is in part pale colored and in part strongly 
pleochroic. The grains of the latter extinguish together producing 
with the former a micro-poicilitic structure. One of the specimens ex- 
amined came from South Rewah and the other from the Mysore State. 
* Journ. Geol., Vol. IV, p. 160. 
5 Ann. Report State Geol, of New Jersey for 1895. Trenton, New Jersey, 
1896, p. 21-61. 
ê Mineralogical Magazine, Vol. XI, p. 56. 
