Stratigraphy of North Dakota

Abstract

ABSTRACT The entire geologic section for North Dakota is not yet known, but all systems, except possibly the Cambrian, are known to be represented. Pre-Mississippian formations underlie the Lake Agassiz silts in the Red River Valley and are continuous with outcrops in the Winnipeg area. Canadian formation names have been applied to these. Rocks of Mississippian through Jurassic age are present only in the western half of the state, are known only from a few samples and well logs, and are everywhere overlapped by Cretaceous rocks. Upper Cretaceous and Tertiary rocks form the bedrock surface over most of the state. In most places they are overlain by a thin mantle of drift.