Some Canadian Rocks containing Scapolite. 199 
Although these scapolite rocks have been ascertained to 
exist at only four localities, they probably occur abun- 
dantly in various parts of the district from which these 
were obtained, and it is very interesting to note that in his 
study of the Petrography of the Drift of Central Ontario,— 
his materials being collected principally about Cobourg, 
situated about the middle of the southern limit of this same 
district, Dr. Coleman found several specimens of “ scapo- 
lite-diorite schist,” which, judging from his description, 
must be identical in character with the rocks described in 
this paper. : 
Although the derivation of at least a part of the horn- 
blende of these rocks from pyroxene is well nigh certain, 
the derivation of the scapolite from plagioclase, which, as 
before stated, has been pretty clearly proved in the case of 
the Norwegian rock, is not so evident in these similar 
rocks from Canada. There is certainly nothing in the sec- 
tions fatal to this supposition, and several facts mentioned 
in this description of the slides seem to give some support 
to it. A much more exhaustive study of the rocks in their 
relations to the pyroxenic and dioritic rocks of the district . 
would, however, be required to decide the question, and 
such an investigation would probably throw additional 
light on the curious paramorphism which the constituents 
of some rocks undergo, apparently under changed condi- 
tions of pressure. Fouqué’s experiment, referred to 
above, on the minerals resulting from prism of the Norwe- 
gian rock, is of especial interest in this connection, as 
tending to show that hornblende and scapolite are not 
stable forms at high temperatures, at least under the ordi- 
nary pressure. The whole question is one of much interest, 
and one which, of late, has attracted a good deal of atten- 
tion.’ 
As mentioned above, the rocks from McDougall and 
Palmerstone occur associated with crystalline limestones 
'See Williams on The Gabbros and Associated Hornblende 
tocks occurring in the neighbourhood of Baltimore, Md., p. 49. 
3ull, U, 8. Geological Survey, No. 28. 
