220 The American Naturalist. [March, 
aegerine particles in a mass of nepheline and apatite, the proportional 
quantities of the three minerals present being about 12 per cent. of the 
first named mineral, 86 per cent. of nepheline and 2 per cent. of apa- 
tite. The orthoclase bearing porphyritic rock referred to above, is 
intermediate in composition between genuine iolite and urtite. 
The Anorthosites of the Rainy Lake Region.—Coleman‘ 
describes a number of additional occurrences of anorthosite near Bad 
Vermilion Lake, Ontario. The rock is in the main a white aggregate 
of bytownite or anorthite with the addition of a little chlorite or ser- 
pentine and an occasional augite grain. The plagioclase grains are 
often idiomorphic, and in some places the anorthosite passes into a 
porphyritic gabbro. Often the feldspars are enlarged by newly formed 
labrodorite, and in one section a bytownite crystal has been broken 
apart and its fragments cemented by the more acid plagioclase. The 
author dissents from Lawson’s view that the anorthosite in this region 
represents the denuded core of an old volcano, which later extruded 
granite. He is inclined to regard the basic rock as much older than 
the acid one. Analysis: 
SiO, AljOs FeO; FeO MnO CaO MgO NaO K,O CO, Total Sp. Gr. 
46.24 1.30 212 tr 16.24 241 1.98 .18 1.08 — 101.35 2.85 
Coleman suggests that all the rocks consisting almost exclusively of 
plagioclase shall be called plagioclasites, and the name of the plagio- 
clase which is their principal constituent shall be prefixed to this. Ac- 
cording to this scheme the name of the rock described above would be 
anorthite-plagioclasite. 
Volcanic Rocks of the Fox Islands, Maine.—Reference has 
already been made in these notes to the existence of volcanic rocks in 
the islands of North Haven and Vinal Haven. Smith® has recently 
made a very careful examination of these rocks from both a geological 
and a petrographical standpoint. He finds the rocks on North Haven 
to consist of diabase schists and schistose tuffs, a series of acid volcanics 
and a small area of Niagara slates, limestones, etc. Vinal Haven is 
made up of acid volcanics, a series of fragmental schists and large 
masses of granitic and basic intrusive rocks in addition to acid vol- 
canics like those found on the northern island, The greenstone schists of 
3 Ramsay: Aft. u Geol. Féren i Stockh. Förh. 18, 1896, p. 459. 
* Journal of Geology, IV, p. 907. 
5 The Geology of the Fox Islands, Maine. Pub. by the author. Skowhegan, 
Maine, 1896. 
