Part I. Stratigraphy: Introduction
The broadly generalized descriptions of southern Appalachian Cambrian stratigraphy thus far published present an imperfect picture. Details are available only for a few restricted areas or for individual sections. Division into the formations has been almost entirely on a lithologic basis, which on the whole is quite satisfactory, though this method of stratigraphic work has not permitted correlation with any high degree of exactness. Previously no complete study has been made of a fauna or of a collection from a specific locality. Most of the older fossil collections unfortunately are neither adequate nor accurately placed as to locality and horizon. Some of these deficiencies can be corrected, but others must await re-discovery of the particular fossils in the field before their stratigraphic positions can be fixed.
Thus it appears desirable to attempt definition of stratigraphic units as accurately as available information permits, and description of the common or diagnostic fossils. Even though these objectives are not wholly reached in this paper more intelligent field investigation should be facilitated. It is hoped further that this study will inspire detailed investigations by others so that a full understanding of the southern Appalachian Cambrian beds may be achieved before many more years pass.
In order that the discussion may be more readily understood the southern Appalachians are divided into several sectors from north to south. Excluding central Pennsylvania, it is convenient to use the following subdivisions: Susquehanna River to the Potomac River; Potomac River to the vicinity of the . . .