s concretions, resembling an amygdaloidal rock. On our first
journey down the Coppermine River, we visited a valley where the Indians
had been accustomed to look for native copper, and we found there many
loose fragments of a trap rock, containing native copper, green
malachite, copper glance, and iron-shot copper green; also trap
containing greenish-gray prehnite with disseminated native copper,
which, in some specimens was crystallized in rhomboidal dodecahedrons.
Tabular fragments of prehnite, associated with calc-spar and native
copper, were also picked up, evidently portions of a vein, but we did
not discover the vein in its original repository. The trap-rock, whose
fragments strewed the valley, consists of felspar, deeply coloured by
hornblende. A few clumps of white spruce trees occur in the vallies of
the Copper Mountains, but the country is in general naked. The
Coppermine River makes a remarkable bend round the end of these hills.

After quitting the Copper Mountains, and passing a valley occupied by a
chain of small lakes in lat. 67 degrees 10 minutes, long. 116 degrees 45
minutes, we travelled over a formation whose prevailing rocks are
spotted sandstone and conglomerate, and which forms the _height of land_
betwixt Bear Lake and the Coppermine River. The ascent to this height
from the eastward is gradual, but the descent towards Bear Lake is more
rapid. The country is broken and hilly, though the height of the hills
above the sea is perhaps inferior to that of the Copper Mountains. The
vallies through which the small streams that water the country flow, are
narrow and deep, resembling ravines, and their sides are clayey. The
ground is strewed with gravel.

The _sandstone_ has very generally a purplish colour, with gray spots of
various magnitudes. It is fine grained, hard, has a somewhat vitreous
lustre and contains little or no disseminated mica.

The _conglomerate_ consists of oval pebbles of white quartz, sometimes
of very considerable magnitude, imbedded in an iron-shot cement. Many of
the pebbles appear as if they had been broken and firmly re-united
again. The conglomerate passes into a coarse sandstone.

Porphyry and granite form hills amongst the sandstone strata.

The _porphyry_ has a compact basis, like hornstone, of a dull brown
colour, which contains imbedded crystals of felspar and quartz, and
occasionally of augite. It forms some dome-shaped and short conical
hills.

The _granite_ is dis