OF DENISON UNIVERSITY. 
12 I 
The most detailed account of the relations between the schists and 
granite seems to be that of McFarlane, who says: “The manner in 
which these Huronian rocks adjoin those of the Lawrentian series may 
be observed on the north shore between Michipicoten Harbor and 
Island. I paid some attention to that point of junction which lies to 
the west of Eagle R. , the precipitous cliffs to the east of which consist 
principally of diabase schist and greenstone slate. A few miles to the 
west of these cliffs and at a point bearing N. 29°, 5° E., from the east 
end of Michipicoten Island, the Lawrentian granite is penetrated by 
enormous dykes of dense basaltic greenstone (having the peculiar 
doleritic glitter when fractured) which contain masses of granite. 
This greenstone is also seen in large masses, which can scarcely be 
called dykes, overlying the granite and enclosing huge masses of that 
rock, one of which I observed to be cut by a small vein of the green- 
stone. From this point to the Eagle R. these two rocks alternately 
occupy the space along the shore, seldom in such a manner as to show 
any regular superposition of the greenstone on the granite, but almost 
always more or less in contact with each other. The greenstone how- 
ever, becomes more frequent towards the east and at Eagle R. it has 
almost replaced the granite, and assumed a lighter color, and an ir- 
regularly schistose structure. The strike of these schists is at places 
quite inconstant ; they wind in all directions, and what appear at first 
sight to be quartz veins accompany their contortions. On closer in- 
spection, however, of the largest of these, they are seen to be of gran- 
ite, but whether twisted fragments of that rock or really veins in it, is 
at first glance very uncertain. ^ ^ ^ Although they are seldom 
or never angular they can scarcely be regarded otherwise than as frag- 
ments whose shape has been modified by contact with the greenstone. 
* * * Either the granite forms veins, penetrating the schistose 
greenstones, in which case the latter are the older rocks ; or it is in 
the form of contorted fragments, in which case the enclosing rock 
may be of eruptive origin. The latter supposition seems to be most in 
harmony with the facts stated.” (Rep. Progress 1863-66.) Com- 
menting on this account Whitney and Wadsworth remarked: “It 
seems almost incredible that a geologist, who professed to be a litholo- 
gist, should have been unable to ascertain the relations and relative 
age of these rocks when so many excellent exposures were observed, 
as he states. His observations show clearly that both formations here 
are eruptive and of the same geological age.” (Azoic System, p. 346.) 
