Whitesail Lake Map-Area
Structural Relations

The rocks on Verdun hill form an upfaulted block in which the beds
strike south 65 to 75 degrees east and dip 25 to 75 degrees to the north.
Faulting is evident along the southern boundary of the assemblage where
the rocks are sheared in a direction north 75 to 90 degrees east and in which
the plane of shearing dips 45 to 85 degrees south. Relations at the other
boundaries are obscured by overburden. To the north the rock surface
descends into a heavily timbered depression. About a mile west of the hill
a fine conglomerate considered to be part of the Hazelton group occurs in
small outcrops. No contact between the two rock types was observed.

The rocks of the Takla group near Eutsuk Lake are separated from
the main belt of Hazelton group rocks by a wide drift-filled valley, which
runs southeast from Connelly Bay on Eutsuk Lake. The rocks on each side
are perceptibly different, strongly indicating the possibility of a fault down
the valley. If this is the case then it is possible that there also the two groups
are in fault contact.

The massive andesites in this locality are cut by stocks of the Coast
Intrusions. The contacts are commonly sharp with silicification of the flow
rocks restricted to a narrow rim close to the contact. Commonly the flows
are traversed by joints having more or less random attitudes.

Age

Only in the rocks composing Verdun hill were any fossils found that
were diagnostic as to age. There some of the tuff and argillite contained
large numbers of the pelecypod Halobia which, according to F. H. McLearn
of the Geological Survey, designates an Upper Triassic age. No fossils or
structural evidence as to age were found in the rocks around Eutsuk Lake,
but Tipper (1955) found that, farther east in the Nechako area, these rocks
were structurally older than those of the Hazelton group and that fossils
collected in them near Bryan Arm on Tetachuck Lake were most probably
of early Jurassic age.

Correlation

In Whitesail Lake map-area rocks included with the Takla group are
lithologically and stratigraphically similar to the Takla rocks in the type
area at Takla Lake and those that are so widespread in Fort St. James,
McConnell Creek, Aiken Lake and Manson Creek map-areas. Elsewhere

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