A Revision of the Lower Paleozoic Stratigraphy in Eastern Vermont

Abstract

The rocks between the Northfield slate and the Gile Mountain formation in east-central Vermont can be distinctly divided into three mappable lithologic units. The western two units are continuous with the Barton River and the Westmore formations as denned in the Memphremagog quadrangle to the north. Hitherto these two units have been included within the Waits River formation, a thick sequence of calcareous and non-calcareous rocks in the Barre and East Barre quadrangles. An analysis of the minor folds and cleavage-bedding relations in the area indicates the possibility of correlating the Westmore formation with the Gile Mountain formation across the limbs of a major syncline, the trough of which is occupied by the calcareous unit in the central part of the East Barre quadrangle. If correct, this interpretation makes this calcareous unit the youngest unit in the Paleozoic sequence of Vermont and hence calls for a revision of the stratigraphic sequence in eastern Vermont. It is proposed that the name "Waits River formation" be restricted to this youngest calcareous unit, inasmuch as the type locality-Waits River village-is situated in this unit and excellent outcrops are present nearby. Also, in view of the foregoing subdivision, the total section of rocks included under the "Waits River formation" of Currier and Jahns (1941) may be redefined as the "Barre group," composed of Barton River, Westmore, and the present Waits River formations.