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perupaeees in size and ruggedness anything clse in the vicinity
of the railway in either tho Coast or Bulkley mountains.

The rocks of Bulkley and Babine mountains are largely
volcanics and sediments cut by small, granitic, intrusive bodies.
These bodies commonly form the cores of the isolated mountains
and mountain groups, or of prominont hills. They are largest
and most abundant near Hazelton where the mountains are the
highest and the mountainous areas most extensive. They occur
elsewhere mainly in prominent mountain areas, but in places they
are marked only by small hills. Granitic and related dykes occur
in many other mountainous parts, especially the less prominent
ones to the south in Babine mountains. They are much more
abundant in the mountains than in the extensive low areas. The
relationship of these intrusive bodies to the mountain areas is
of great importance since the mineral deposits are related to,

and occur near or in, them. The mountain arcas, therefore, are

the most favourable for the occurrence of metallic mineral

deposits and it is in them that all but a few have been discovered.

Sediments and Volcanic Rocks.

The sedimentary and volcanic rocks of Bulkley and Babine
mountains are mainly Mesozoic, ranging from Jurassic and possibly
Triassic to Upper Cretaceous. Out of the various groups into
which the Mesozoic rocks have been subdivided in the different
areas studied only one, the Lower Cretaceous or Skeena formation,
stands out as a fairly readily identifable unit in all sections.
It is largely sedimentary with minor amounts of tuffs. The
other rocks so far as this report is concerned do not need to be
carefully classified. They have been subdivided largely on
lithological bases. Some of the groups, one of which includes
the oldest rocks and others of which are probably considerably

younger, consist largely of massive volcanic rocks. These are