The St. Mary River and Willow Creek Formations of Montana offer unequalled opportunities for the study of Late Cretaceous dinosaur faunas from upper coastal plains environments and particularly for the analysis of habitat bottlenecks and their effect on extinction and radiation of large bodied terrestrial from the Johns Hopkins University School of Medicine in 1986 make it certain that further exploration will yield important additions to our knowledge of the Late Cretaceous biota of the western interior of the U.S. It is proposed (1) to devote two field seasons to collecting, mapping, and detailed stratigraphic work in the St. Mary River and Willow Creek Formations (including areas only reconnoitered in 1986); (2) to analyze the three or more distinct types of eggs collected from the St. Mary River Formation; (3) to describe the juvenile and embryonic dinosaur remains (both material in hand and expected finds); (4) to describe the adult dinosaurs and other associated reptiles; and (5) to draw what conclusions are justified from the previously mentioned data about the evolution of the St. Mary River and Willow Creek dinosaurs, with special reference to their relationship to the opening of terrestrial habitats through the regression of the Bearpaw Sea.
