Correlation of Cambrian–Ordovician boundary between Europe and North America: new data from western Newfoundland

The Cow Head Group in western Newfoundland includes a record of continuous graptolite evolution across the Cambrian–Ordovician boundary. In sections at Broom Point, interbedded breccias contain blocks with rich platform trilobite faunas which give a complete succession of North American zones. The s...

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Bibliographic Details
Published in:Canadian Journal of Earth Sciences
Main Authors: Fortey, Richard A., Skevington, David
Format: Article in Journal/Newspaper
Language:English
Published: Canadian Science Publishing 1980
Subjects:
Online Access:http://dx.doi.org/10.1139/e80-036
http://www.nrcresearchpress.com/doi/pdf/10.1139/e80-036
Description
Summary:The Cow Head Group in western Newfoundland includes a record of continuous graptolite evolution across the Cambrian–Ordovician boundary. In sections at Broom Point, interbedded breccias contain blocks with rich platform trilobite faunas which give a complete succession of North American zones. The stratigraphic relationship between graptolites and trilobites clearly establishes that the base of the type Tremadoc Series lies above that of the Missisquoia Zone. The sequence of earliest planktonic graptolites is the most complete known and serves to remove objections to the selection of Dictyonema flabelliforme, or one of its subspecies, as an index for the base of the Ordovician System.