1872..
NICHOLSON NORTH SHORE OF LAKE SUPERIOR.
21
Leaving Prince Arthur's Landing by the
Dawson Road, we pass for the first three or
four miles over the black shales and interstra-
tified traps of the " Lower Copper-bearing
series." Four or five miles to the north-
east of Thunder Bay there comes on a range
of syenitic and gneissic rocks of Laurentian
age, as I should imagine by the interven-
tions of an E. and W. dislocation ; and these
continue to be exposed for several miles.
These in turn are succeeded to the N.W. by
a vast series of rocks referable to the Huro-
nian Group(see Map, fig.1 , and section, fig. 2).
The first members of this series consist of
greenish or grey slates, with bands of gneiss
and occasional trap-dykes. At the Govern^
ment post known as the " Fifteen-mile
Shanty," and from here up to the foot of Lake
Shabendowan , a distance of 32 miles, we cross
a succession of bedded traps, mostly green in
colour, interstratified with great masses of
greenish, grey, or drab-coloured slate. The
road runs a little to the north of west, and
the general strike of the beds is W. by IS .
and E. by S. ; so that the actual thickness
of beds crossed over, though very consider-
able, is not so great as might at first sight
appear to be the case. These Huronian
slates and traps present a most singular
resemblance to the green slates and por-
phyries of the Lake -district of the north
of England. This likeness is shown in their
mode of weathering, in the kind of scenery
produced, and especially in the lithological
character of the slates. The slates in ques-
tion have a prevailing green colour, are
usually fine-grained, but are not unfre-
quently brecciated, and are divided by a
more or less nearly vertical cleavage, the
direction of which is remarkably persistent
over very large areas. The surfaces of the
slate are not uncommonly glossy ; and in
some cases, at any rate, tbe cleavage ap-
pears to coincide with the bedding of the
rock. These slates have been generally
spoken of as " talcose" or "chloritic" slates ;
but I entertain no doubt that they are truly
of the nature of bedded felspathic ashes.
They do sometimes contain talc, and are
occasionally serpentinous ; but I am satisfied
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