Introductory. The granitic rocks of Missouri are the only massive crystallines occurring between central Arkansas and lake Superior and between the Appalachians and the Rocky mountains. They are the most ancient rocks exposed in the central Mississippi basin. As irregular, discontinuous fields and isolated hills the crystalline masses are scattered over a district of more than 3,000 square miles, in the southeastern part of the state. They are all igneous in origin and pre-Cambrian in age.
Important as the region is as a mining district, and as much as has been done toward an inquiry into the nature of the mineral deposits, it is somewhat remarkable that so little attention has been paid to deciphering the stratigraphy of the region. Only very recently have the stratified rocks begun to receive serious attention, while until lately, when their consideration was taken up by Haworthaccording to modern petrographical methods, hardly anything . . .
- © 1895 Geological Society of America