amygdaloidal is a volcanicrock texture in which small volatile cavities or vesicles are filled with secondary minerals.
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The amygdaloidal cavities carry stilbite, mesolite, heulandite, and a fluorine-bearing apophyllite, as well as copper; the copper seems to be the oldest of these minerals and is found upon the walls of the cavities.
Both sulphides and native copper are disseminated in the amygdaloidal portions of the basalt and in veins.
In the Bathurst Inlet region the copper occurs disseminated in the traps, in the amygdaloids, and in fissures.
Amygdaloid pebbles are present in most of the felsite conglomerates, and locally such basic material may become plentiful, but fragments of trap are decidedly unusual.
In the sections and maps this and similar beds have been classed under the term "scoriaceous amygdaloids," a term well established in the records of the district, though it is recognized that "amygdaloidal conglomerate" conveys a better idea of their probable mode of formation.
The felsite sediments are characteristically underlain by amygdaloidal conglomerate.
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