From Preface: "The present account summarizes the results of a long investigation of the rocks of the Great Smoky Mountains (1946-55) by geologists of the staff of the U.S. Geological Survey, in collaboration with those of the Tennessee Division of Geology. The technical details of this investigation have already been set forth at length in professional papers of the U.S. Geological Survey. The present account contains the gist of these findings about the rocks of the mountains, and is accompanied by a map and structure sections in which the surface and underground extent of the rocks are displayed."