OB' DENISON UNIVERSITY. 
133 
ance of the section, otherwise is identical. Here, too, the adja- 
cent schist has assimilated itself to it most remarkably in general ap- 
pearance, though a glance at a section shows it to be of a quite distinct 
character. It is really an aliered mica schist (!) consisting of quartz, ‘ 
chlorite, much calcite and iron salts. This fact that certain eruptives 
have the power to assimilate the adjacent rocks so closely in external 
appearance as to defy recognition, while not altering the real nature 
of the rock, needs to be constantly borne in mind by field-geologists. 
These rocks, classed as greenstone slates and. considered as eruptive 
by previous writers, can with care be readily separated into interbed- 
ded sedimentaries and eruptives. A succession of such dykes is 
seen east of Eagle river. West of Eagle river, especially on the jut- 
ting point referred to by McFarlane, the schist suffers the extreme of 
metamorphism, being twisted and gnarled in every conceivable way, 
at the same time seggregating various minerals in pockets and lenticu- 
lar masses. Veins of granite perforate the schist and include it in ir- 
regular masses. The effect of such intrusive action is here well seen. 
The fragments of schist so inclosed are angular and though often fused 
into the granite, never permit comparison with the Dog river conglom- 
erate. A direct comparison of this sorf may bring out relations hard 
to verbally explain. The contact samples show much epidote which 
. forms zones at the contact, veins in the schist, or replaces the horn- 
blende in the granite. At this point is this immense dyke No. 1056. 
No. 1058 is schist at the contact and consists almost entirely of 
epidote containing strings and fragments of the aphanitic margin of 
1056. Westward the granite constantly encroaches on the schist, 
which is here a typical mica schist of fine texture. 
The diabases, as before stated, are exceedingly monotonous in 
composition and structure. A considerable range of variation in the 
relative size of the ingredients is the chief divergence. They never 
carry an appreciable amount of olivine and the feldspars are either lab- 
radorite or labradorite and oligoclase, the former with brilliant polari- 
zation colors and distinct outlines. 
No. 1056 may* be taken as a type of the whole series. This is 
especially interesting as being the dyke northeast of Michipicoten 
island, called, by McFarlane, doleryte and considered by him and by 
Wadsworth after him, as one of the sources of the schist. This is 
