Abstract

Combined paleontological evidence from the western and northern structural units of Newfoundland (the autochthonous St. George, Table Head, and Goose Tickle Groups, and the allochthonous Cow Head and northern klippen sequences) reveals an almost uninterrupted succession of the North American graptolite Zones 1 through 9 (of Berry, 1960). Only Zone 7 has not been verified. In Berry's Zones 1 and 9, the zonal record is extensive enough to justify subdivision into separate zones, whereas some other zones appear to be lithologically condensed.

A recently discovered Early Ordovician Dictyonema flabelliforme-Staurograptus fauna from an unknown allochthonous formation at Onion Cove, northern Newfoundland, is provisionally referred to the mobile belt facies and appears to be related to similar occurrences in Nova Scotia and western Europe. Most of the autochthonous and allochthonous sequences contain graptolites with strong Pacific-American affinities, but one graptolite association with Baltic-British affinities has been found in the Goose Tickle Formation of northernmost Newfoundland.

Except for the deep-water environment of the Goose Tickle strata, all other autochthonous formations were deposited under shallow sublittoral conditions with only sparse graptolites preserved. The argillaceous beds of the Cow Head allochthonous complex probably have been brought in from a rapidly subsiding miogeosynclinal shelf margin intermittent between the circumcratonic limestone belt and the mobile belt in the east. A “pre-klippen” reconstruction of the Cow Head sequence and correlations of the graptolite facies suggest the existence of a “pre-Atlantic rift” belt, a Pacific development of graptolite associations along the “Logan's Zone” of the Appalachians to western Ireland and Atlantic Norway, and a contrasting Baltic faunal development having temporarily encroached on northern Newfoundland during Goose Tickle time.

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