Revision of the March Formation (Tremadocian) in Southeastern Ontario

Abstract

Reference sections are proposed for the revised March Formation (Tremadocian) along the MacDonald–Cartier Freeway a few miles west of Brockville, Ontario. The sequence of the March Formation delineated by these sections yields nearly a complete stratigraphic succession for this formation in southeastern Ontario. The lithology, thickness, and sedimentary environment are described, and the known conodont fauna is recorded.The establishment of a nearly complete reference section allows better understanding of the March as represented in the type area west of Ottawa, Ontario and permits more precise definition of the upper and lower contacts of the formation. The upper boundary of the March Formation as revised coincides with a probable Tremadoc–Arenig boundary: the lower boundary, also lithologically distinct coincides with the abrupt first appearance of conodonts in the Lower Paleozoic succession in southeastern Ontario.