The Llandovery—Wenlock Halysitidae from New Brunswick, Canada

Abstract

A large collection of Silurian halysitids, mainly from the Limestone Point, La Vieille, and Petit Rocher Formations of northern New Brunswick, includes nine species distributed among Catenipora Lamarck, Halysites Fischer von Waldheim, and Cystihalysites Tchernyshev. One species, Cystihalysites belledunensis, is new, and, of the others, half are previously unknown in the Chaleur Bay region and half have been described before from this area.All species are defined using both qualitative and quantitative data. Statistical analysis of serial sections of a corallum of Cystihalysites belledunensis suggests that any random section of a halysitid will yield quantitative data representative of that colony.Preliminary analysis of the relationships between species distributions and stratigraphy and sedimentary associations suggests strong facies-control on the distribution of the four most abundant species. Both Catenipora simplex (Lambe) and Catenipora micropora (Whitfield) occur mostly in outer shelf facies. Cystihalysites belledunensis n. sp. and Cystihalysites encrustans (Buehler) never occur together, the former being found in predominantly high-energy inner shelf facies and the latter in the outer shelf facies.