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the extension of these seas, or sea, southward along the site of the Rocky
Mountains. The Norian Monotis alaskana or Himavatites sea inundated
not only most of northeastern British Columbia, but parts of the Yukon
and Alaska as well; although this sea occupied a large area in northwestern
North America, the fauna included species remarkably close to some in a
fauna of similar age in the East Indies. The late Norian and northern
Monotis subcircularis sea extended south along the Rockies at least to
Athabasca River Valley (Vine Creek) and northwest and west over large
areas in British Columbia, the Yukon, and Alaska.

The red, gypsiferous beds in the Guardian well, near the eastern border
of the present map-area, and in the Mowitch Range far to the south (Allan,
1933), may record a shallow sea, possibly near the eastern shore, with
excessive evaporation. Not much is known, however, of this phase of
the Triassic.

LATE TRIASSIC EMERGENCE

No beds of Rhaetic, that is late Upper Triassic, age have yet been
found in British Columbia or Alberta. The northern part of the continent
may have been completely emergent at this time.

JURASSIC SEAS

Karly in Lower Jurassic time northeastern British Columbia was
again flooded by the sea. Details are lacking, but the Jurassic seas, or
sea, are known to have covered western and southern Alberta, large areas
in British Columbia, and parts of Yukon and Alaska,

AUCELLA SEAS

The marine phases of the Nikanassin formation in Alberta, and the
lower part of the Bullhead group in northeastern British Columbia, record
& sea or several successive seas on the site of the Foothills. They may
have spread south as far as Athabasca River Valley, and may have been
invasions from the Arctic Sea following a path somewhere west of Mac-
kenzie River Valley. The later of these Aucella seas is probably of early
Lower Cretaceous age and the earliest is possibly of very late Jurassic or
very early Lower Cretaceous age (See Chapter III).

CRETACEOUS LANDS AND SEAS

The alluvial plains and swamps recorded by the Kootenay formation
of the southern Foothills and Mountains may or may not have been
deposited marginal to a sea. Those recorded by the Gething, Lusear,
and lower Blairmore beds may have been deposited marginal to a sea,
but to what sea is at present uncertain. All of the late Lower Cretaceous
and all of the Upper Cretaceous alluvial plains are marginal to a sea, and
were built out into them as deltas. These deltas formed in shallow seas
in a subsiding basin, and not in a deep body of water with stationary floor.
They were of the Mississippi type of delta rather that that of Lake Bonne-
ville (Barrell, 1912; Storm, 1945), and may be called marginal alluvial
plains or deltas.

All non-marine Cretaceous formations of the Canadian western in-
terior, like those of the United States interior (Bartram, 1937; Pike, 1947 ;