Stratigraphy of the Kimmswick Limestone of Missouri and Illinois

Abstract

In this paper the general results of the writer's study of the large fauna oi the Kimmswick limestone are presented. The description of species is to be published elsewhere. The study has demonstrated the marked faunal homogeneity of the formation vertically as well as horizontally, and from different types of evidence establishes the age of the Kimmswick as early Trenton rather than late Black River. Although essential contemporaneity is postulated for the Kimmswick and the Prosser of Minnesota, certain faunal differences strongly suggest a barrier between the northern and southern Mississippi Valley in early Trenton times. Evidence is presented to show that part of the Kimmswick fauna reached the lower Mississippi Valley by way of the Appalachian Valley, while another faunule seems to have entered from the west.