The Supai Group Subdivision And Nomenclature

The Supai Formation of the Grand Canyon region is raised in rank to Supai Group and divided into four formations that range in age from early Pennsylvanian to early Permian.

Excerpt from The Supai Group: Subdivision and Nomenclature Probably the first geologist to carefully consider subdivision of the Supai Formation into logical, readily recognizable units was F. E. Matthes of the us. Geological Survey. In making a topographic map of the Bright Angel quadrangle in 1902-3, he noticed that the red beds of this formation, together with the overlying Hermit Shale, characteristically eroded into three prominent cliffs, interspersed among four well developed slopes. The discrimination of these topographic units was called to my attention by Matthes in the 1930's in connection with my studies of the Supai Formation. A field classification that proved useful in recording data at that time and in all subsequent work resulted. Subdivision of the Supai on the basis of topographic expression, used during the present field-investigation, recognized the following units: Upper cliff unit, locally includes a receding ledge unit (esplanade cliff) About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Nine short papers present changes in stratigraphic nomenclature in California, Nevada, Arizona, Kentucky, Tennessee, Ohio, Georgia, South Carolina, and Massachusetts, and a revised Mississippian time scale for the western interior region of the United States.