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in places feldspathic, in a belt about 8 miles wide trending across the
strike of the rocks. Strata 5 miles to the northwest and 2 miles southeast
of this belt, which almost certainly represent the same beds as the
garnetiferous rocks, are the normal sericitic slates and phyllites, quartz-
chlorite schists, and quartz-pebble conglomerates of the Ingenika group.
With increasing grade of metamorphism, the garnets apparently disappear,
the quartzite pebbles in the conglomerates recrystallize into long lenses
of crystalloblastie quartz, the proportion of feldspar increases, and the
rocks grade into quartz-mica-feldspar schists and gneisses. Such a
sequence of changes is revealed on the ridge due north of Tomias Lake,
and on the flank of the mountain southwest of the outlet of the lake.

Quartz-mica-feldspar Gneiss

The beds of feldspathic quartzite and quartz-mica-feldspar schist grade,
along their strike, into more coarsely granular rocks in which the individual
beds lose their identity, but which possess a pronounced banded structure
due to segregated layers rich in biotite or in quartz and feldspar. Most
of these rocks are composed mainly of grains 1 mm. or more in size. The
tendency toward development of the oriented, elongate grains of quartz and
feldspar is much less pronounced in these rocks than in the schistose quartz-
ites from which they were derived, and the foliation of the gneiss is due
mainly to the ragged but fairly well oriented flakes of biotite, and to a
segregation of the minerals into layers relatively richer in quartz or in
biotite.

Most of the gneisses contain about 50 per cent feldspar, apparently
mainly albite-oligoclase or microcline. The proportions of these two types
vary widely in different specimens. Some rocks are composed almost
entirely of biotite and microcline. In one section, an untwinned, optically
negative feldspar, probably orthoclase, is associated with the microcline.
A few of the gneisses contain conspicuous porphyroblasts of albite-oligo-
clase, usually zoned, with well-developed albite and Carlsbad twinning, and
clouded with inclusions, up to 6 mm. long. The potash feldspar was not
observed to be porphyroblastic in habit, but in at least one specimen
several smaller grains are collected into irregular, lenticular augen up to
10 mm. long.

Migmatite

There is no sharp distinction between the quartz-mica-feldspar gneisses
of the Wolverine complex and those rocks to which the term migmatite has
been applied. However, it has been found useful in the field to distinguish
those gneisses that contain bands, or, more rarely, irregular patches with
vague, gradational borders, of granular crystalline material in which the
various constituents are evenly distributed, and which, in hand specimen,
have a markedly ‘igneous’ aspect; such rocks have been called migmatites.
They are best developed around the granodiorite stocks southeast of Black-
pine Lake, where they may be traced along the foliation through less
metamorphosed gneisses into schistose quartzites. A small area of similar
rocks is exposed on the ridge east of Tomias Lake.