hen the vallies are of considerable extent, they are almost invariably
occupied by a lake, the proportion of water in this primitive district
being very great; from the top of the highest hill on the Hill River,
which has not a greater altitude than six hundred feet, thirty-six lakes
are said to be visible. The small elevation of the chain may be inferred
from an examination of the map, which shows that it is crossed by
several rivers, that rise in the Rocky Mountains, the most considerable
of which are the Churchill and the Saskatchewan, or Nelson River. These
great streams have, for many hundred miles from their origin, the
ordinary appearance of rivers, in being bounded by continuous parallel
banks; but on entering the primitive district, they present chains of
lake-like dilatations, which are full of islands, and have a very
irregular outline. Many of the numerous arms of these expansions wind
for miles through the neighbouring country, and the whole district bears
a striking resemblance, in the manner in which it is intersected by
water, to the coast of Norway and the adjoining part of Sweden. The
successive dilatations of the rivers have scarcely any current, but are
connected to each other by one or more straits, in which the
water-course is more or less obstructed by rocks, and the stream is very
turbulent and rapid. The most prevalent rock in the chain is gneiss; but
there is also granite and mica-slate, together with numerous beds of
amphibolic rocks.

LIMESTONE OF LAKE WINIPEG.

To the westward of the chain of primitive rocks, through a great part,
if not through the whole of its course, lies an extensive horizontal
deposit of limestone.

Dr. Bigsby, in the Geological Transactions, has described, in detail,
the limestone of Lake Huron, and is disposed to refer "the cavernous and
brecciated limestone of Michilimackinac to the magnesian breccia, which
is in England connected with the red marl;" whilst the limestones of St.
Joseph, and the northern isles, he considers as more resembling the
well-known formation of Dudley, in Staffordshire. The limestone of
Thessalon Isle, in which there occurs the remarkable species of
orthoceratite which he has figured, he describes as decidedly magnesian.
I observed this orthoceratite in the limestone strata of one of the
isles forming the passage of La Cloche in Lake Huron. The limestone
deposits of Lake Winipeg and Cape Parry exactly resemble that of La
Cloche in minera