MIDDLE CAMBRIAN OF AVALONIAN MASSACHUSETTS: STRATIGRAPHY AND CORRELATION OF THE BRAINTREE TRILOBITES

摘要: Abstract Although Middle Cambrian trilobites of the Braintree Member in eastern Massachusetts were among first published on North America, re-examination this fauna has led to wholesale taxonomic and biostratigraphic re-evaluation. This low diversity now includes at least seven species, with report agnostoids (three poorly preserved taxa) ellipsocephalid Kingaspis avalonensis new species. Paradoxides (Acadoparadoxides) harlani Green emend., a senior synonym P. (A.) haywardi Raymond, allows correlation into lowest elsewhere Avalon. However, all polymeroid species are endemic, precludes highly resolved other paleocontinents. A breakdown provincial barriers late Early as western Gondwana passed from equatorial higher south latitudes Avalon faunal exchanges between these continents. shared wester...