Jurassic-Cretaceous biochronology and paleogeography of North America : the proceedings of a symposium held in honour of Ralph W. Imlay and George W. Jeletzky at the 3rd North American Paleontological Convention in Montreal, Quebec, August 6th, 1982 / - Imlay, Ralph W.; Jeletzky, J. A.; Westermann, G. E. G. (Geological Association of Canada, Dept. of Geology, Memorial University of Newfoundland, 1984)