Abstract

Introduction

The name Alexandrian series2 was proposed by the writer in 1908 in order to provide a place for the earliest Silurian strata occurring in Illinois and eastern Missouri which occupy a position above the top of the generally accepted Cincinnatian (Richmond) and below the Brassfield (Ohio Clinton) limestone.

Regarding the stratigraphic position of the Brassfield, Professon Schuchert3 states in his classic work on the Paleogeography of North America that β€œin the Anticosti section it is seen that this so-called Clinton (Ohio Clinton) or Triplecia ortoni zone is older than the true Clinton of the Appalachian region.” It is now also known that the fauna of the Brassfield limestone is very closely allied to that of the earlier Silurian strata of Illinois and eastern Missouri, as shown in the similarity of several of the genera and species to those of the older Edgewood limestone. For this reason the strata representing . . .

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