LATE PALEOZOIC CONIFERS OF NORTH-AMERICA - STRUCTURE, DIVERSITY AND OCCURRENCES

Late Paleozoic conifer communities originated in moisture-stressed env ironments along the paleoequator on the Laurussian continent. By Late Permian time, northward movement of the continent displaced these comm unities toward subequatorial regions. North American deposits provide the most abundant and best preserved pre-Permian conifer fossils. They represent a wide spectrum of preservational modes including compressi on/impression, mold/cast, and cellular permineralization by carbonates , phosphates, iron sulfides, iron oxides and iron hydroxides. Some mod es are associated with distinct biotic assemblages, and to some extent each can be correlated with certain depositional environments and tap honomic histories. Exceptional floras containing extensive conifer rem ains occur in the Rocky Mountains, the Midcontinent, and the Appalachi an regions. These include: estuarine carbonates at Hamilton and Pomona , Kansas; transitional terrestrial to marine clastics at Kinney Brick Quarry, New Mexico, Garnett, Kansas and the 7-11 Mine in northeastern Ohio; and offshore marine shales in Kansas, Oklahoma and Texas that we re deposited in dysoxic environments. Most specimens have been assigne d to the form genus Walchia, but exceptionally well preserved specimen s conform to species of Emporia (Emporiaceae) and to one or more undes cribed species that may represent additional genera and/or families. T hese species add significantly to the growing diversity of Paleozoic c onifers, and provide valuable data for testing hypotheses of conifer a nd coniferophyte relationships.