ABSTRACT
Canada and the United States have karsts and pseudokarsts in many differing terrains, with differing landforms, and with differing spelean histories. In broad terms, the United States has about a dozen major calcareous karst areas and one in gypsum. Canada has almost as many in carbonate rocks, and several in gypsum (see entries on Canada and United States of America). The density and types of caves and other features vary markedly between the areas, and many of their subordinate units have their own history of exploration and study, and of significant events.
