Analysis of Crustal Relative Stability from Some Late Paleozoic and Mesozoic Floral Records1
Plant distribution patterns from later Paleozoic and Mesozoic times were determined from combined evidence of (1) recognized floral provinces of the world, (2) ecotonal areas of admixed taxa from adjacent provinces, (3) geographic distributions of plant genera, and (4) ecological (especially climatic) inferences derived from assemblage analyses. Such data indicate that these patterns conform to continents in approximately their present relative positions. Application of continental drift and attendant paleogeographic reconstructions solve few floral problems that could not be explained otherwise, and create problems that otherwise would not exist. The concepts of continental drift and polar wandering, especially of the magnitude envisaged by their proponents, thus seem precluded by the known floral records from Permo-Carboniferous time to the present; but such records could be considered permissive of the concept of seafloor spreading, provided the lateral displacement of continents was on a much smaller scale. Large-scale continental displacements prior to later Paleozoic times are not precluded by this analysis.