The Talladega belt in Alabama and Georgia is the northwesternmost belt of the Appalachian Piedmont metamorphic province. It contains low-rank metasediments and metavolcanics that have been thrust faulted onto Paleozoic sediments of the Valley and Ridge province via the Cartersville-Talladega fault system. The age of several formations in the southwestern part of the Talladega belt in Alabama has been determined to be Devonian, but controversy exists concerning the age of much of the rest of the belt. Another major problem has been the age and structure relationships of the Talladega belt to the Precambrian and Lower Cambrian rocks of the Blue Ridge province on strike with the Talladega belt to the northeast. In the Borden Springs area, Cleburne County, Alabama, nappes of the Lower Cambrian Weisner and Shady Formations rest on younger Paleozoic rocks immediately northwest of the Talladega belt. A sequence composed mainly of slates and quartzites characterized by graded beds lies between the Talladega belt and the nappes of Weisner and Shady. Distinctive lithologies within this sequence are found also within the Talladega belt near Borden Springs and also near the southwest end of the belt in Alabama within metasediments immediately below the Jumbo Dolomite of the Sylacauga Marble Group. Although the slate-quartzite sequence has been interpreted in recent years as being Ordovician to Devonian, detailed mapping in the Borden Springs area indicates that it is correlative with the Early Cambrian Weisner and Shady, although somewhat different in sedimentary aspect from Weisner and Shady in nappes to the west. Therefore, the Talladega belt may contain rocks at least as old as Early Cambrian and may be at least partly equivalent in age to rocks of the Blue Ridge province. The slate-quartzite sequence lies northwest, west, and southeast of an anticlinal region of younger Paleozoic sediments in western Georgia, over which it was thrust faulted. It thus forms an imbricated nappe sequence rooted, if at all, beneath the Piedmont province to the southeast.

Field investigations started in 1925 by the writer led to a growing interest in the confusing stratigraphic problems of the lower half of the Mississippian system in the east-central interior of the United States, especially in Indiana, Kentucky, Ohio, and to a lesser extent in Tennessee. Studies were first undertaken in southern Indiana where the major part of four summers was spent in the field; this led to the preparation of a detailed report entitled The Borden ( Knobstone ) Rocks of Southern Indiana, published in 1931. This study disclosed numerous problems directed toward the adjoining areas and thus gave impulse to the investigation of additional territory. Soon, therefore, the problems of lower Mississippian rocks were viewed in the light of broader, regional relationships. Necessity was seen for an expansion of detailed field studies in order to clarify issues arising from the study of literature. Stratigraphic correlations were especially perplexing and badly confused. With the aid of a field assistant in the spring of 1934, 14 weeks were spent surveying the lower Mississippian outcrop belt which surrounds the Lexington Plain in Kentucky. This resulted in linking the Indiana studies with those of Ohio. Much less extensive field studies have been made in parts of northern and eastern Tennessee and parts of Ohio, during short portions of the summers of 1930 and 1936. The principal objectives in the preparation of this paper are: (1) To give, in a single report, a summary of the essential elements in the stratigraphy of the entire lower . . .