A fundamental new method has been recently introduced by Gordon et al. (1984) to the analysis of the apparent polar wander (APW) path for North America, based on the concept of a best-fit paleomagnetic Euler pole (PEP). By analogy with hot- spot tracks which also seem to follow small circles, and APW path is proposed to describe long intervals during which the direction of plate motion was constant. The change from a rotation about one PEP to another is described by a cusp, the intersection of two small-circle track segments. A critical test of the novel PEP idea, which in principle allows the complete description of plate motion, is the confirmation of the sharp cusp that results between the Carboniferous to Triassic and Jurassic to Cretaceous tracks for North America. The PI will make a detailed paleomagnetic study of Newark Supergroup rocks which represent a complete stratigraphic succession that encompasses the time interval of the proposed cusp. Location of the cusp within this continuous and well- dated stratigraphic sequence will provide firm evidence of its timing and paleomagnetic signature.
