AREA OF NEPHELINE-BEARING ROCKS 325 
as “igneous rocks” and nothing is said about their supposed vol- 
canic affinities. In the same publication also, p. 467, the occur- 
rence is referred to as follows: 
“On the main shore of Lake Superior, nearly north of the 
western extremity of Pic Island, is a mass of syenitic rock, com- 
posed of red feldspar and hornblende, with zircons which resemble 
the zircon syenite of Norway.” As is well known, this latter 
rock is an augite-syenite, which in Norway is intimately related 
to nepheline-syenite. 
As all the localities mentioned in this note are near one 
another on the same stretch of coast, and in the vicinity of 
Heron Bay, it seems certain that there is in this district a large 
intrusion of an alkali-rich magma, differentiated into various 
rock facies, among which there are some containing nepheline 
and some free from that mineral, and that Dr. Coleman’s Heron- 
ite is connected with the intrusion in question. 
FRANK D. ADAMS. 
PETROGRAPHICAL LABORATORY, 
McGILuL UNIVERSITY. 
