Foliation and Sedimentation — Lawson. 171 
^'summarize briefly the facts which have led him to believe the 
foliation of the gneisses sustains a relation of dependence on an 
antecedent sedimentary structure." 
I shall deal with these propositions, or the more important 
parts of them, seriatim, referring to them by the same numbers 
as are given in Prof. Ws. report.* 
1. Prof. W. says: "The gneissic foliation follows very ex- 
actly the planes of schistic sedimentation. * * * The fact 
is admitted by Mr. Lawson." 
I admit that it is generally true, but in my report I cite ex- 
ceptions where the foliation is transverse or oblique to the 
schistosity, and figure cases on pp. 32, and 73. It is one of 
those questions where the exceptions are of much more import- 
ance than the rule. 
2. Prof .W. says: "No reason can be given for supposing 
subsequent foliation would so closely follow the schistic sedi- 
mentation unless a sedimentation had originally existed in the 
gneisses strictly conformable with that of the schists." 
There are very excellent reasons. I conceive the foliation of 
both the Laurentiau gneiss and the Keewatin schist to be due to 
the same cause acting on rock matter in two different physical 
states. Given a magma crystnllizing into a solid with extreme 
slowness, and passing through a thickly viscid stage prior to 
final solidification; and given in contact with this, a solid rock 
either of sedimentary or volcanic origin, and the whole sub- 
jected, while confined at great depths, to enormous pressures, so 
that the solid rock was not only folded on the large scale but 
sheared in its minute structure, and the crystallizing magma 
caused to flow^ in response to the same pressures, we would have 
eventually, as the result, the very conditions which we find to- 
day at the contact of -the Lnurentian and Keewatin. 
In the same paragraph, speaking of the schists Prof. W. 
* In the preliminary portion of his criticism Prof. W. makes two mis- 
statements which, although apart from the main question at issue, it may 
be as well for me to cf)rrect. He statf s that the Keewatin series of the 
Lake of the "Syoods "is completely isolated from other schists." I state in 
my report (p. 61, CC) that "it occupies an area which presents the appear- 
ance of an almost isolated patch;" and show both elsewhere in my report 
and in my map that the area is continuous with similar rocks to the S. E. 
Prof. W. also states that with me "the sheets interbeddinl with tlie horn- 
blende schists are dykes and belong to a later age and a different mode of 
geologrc^il action." This is a misunderstanding. I have never entertained 
any sucli opinion nor in any way given expression to it. 
