The Marron Formation is a sequence of early Tertiary lavas associated with which are a number of intrusions, referred to as the Coryell Intrusions, which are thought to be consanguineous. Both lavas and intrusions probably extend beyond the area indicated by the map (Fig.
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Approximately 50 km east of Atlin and 2 km north of the Mount Llangorse quartz diorite intrusion five small intrusions of nephelinite cut thermally altered Permian-Pennsylvanian cherts.
Several peralkaline dykes up to a metre thick have been described from the central part of the Atsutla Range. The dykes are banded and contain abundant, zoned spherulites up to 6 mm in diameter of alkali feldspar, albite, quartz, riebeckite and aegirine. Rock analyses are available.
The Itcha Mountains (or Range) are one of the centres of the Anahim Volcanic Belt and consist of a central shield volcano amidst Miocene and Quaternary plateau lavas. The mountains do not appear to have been studied in great detail petrologically.
Boulders of basalt with white, trapezohedral phenocrysts up to 2.5 cm in diamter, which were thought to be leucite, were reported to occur where Horsefly Creek meets Quesnel Lake (Hoffman, 1896), but they were later recognized to be analcime (A.M. Soregaroli, 1973 - quoted in Currie, 1976a. p.
Takomkane Mountain is an isolated volcanic cone with a single lava flow of nephelinite containing abundant xenoliths of spinel lherzolite.
North and northeast of the town of Blue River several sheets of carbonatite have been delineated which are conformable, and commonly sheared and boudinaged.
A northeast-southwest-trending dyke of alnoite, averaging 1.2 m in thickness, cuts sedimentary and volcanic rocks of the Nicola Group (Triassic).
Alkaline rocks occur in an elliptical pluton 3x1.5 km elongated east-west, and a smaller crescent-shaped body to the south.
Sodalite veins are reported by Currie (1976a, p. 101) to occur at Mount Laussedat, 77 km northwest of the Ice River Complex.