The Physiographic Interpretation of the Fall Line
1927; Taylor & Francis; Volume: 17; Issue: 2 Linguagem: Inglês
10.2307/208229
ISSN1931-0846
Autores Tópico(s)Botany, Ecology, and Taxonomy Studies
ResumoW TITHOUT exception, regional physiographers have selected fall line of eastern United States as a boundary between two major physiographic regions, Crystalline Appalachians and Atlantic Coastal Plain. This is due not so much to its physical nature, for physiographic expression of fall line is often slight, but to striking differences in rock structure, soil, vegetation, and types of geographic adjustments on opposite sides of this boundary. The fall line has also a hydrographic and economic significance, for it marks a point of deflection of or declivity in nearly every stream that crosses it. The falls or rapids in streams as they cross fall line interrupt river navigation and before age of coal power offered some of prime power sites of eastern United States. As a result of these two factors, now relatively of less importance, there exists today a long line of cities on or near fall line; Trenton, Philadelphia, Wilmington, Baltimore, Washington, Fredericksburg, Richmond, Petersburg, Columbia, Augusta, Milledgeville, and Macon-most of them seats of important manufacturing. The fall line is often traced by railways, telegraph and telephone lines, roads, and county boundaries, and there is present at nearly every point a strong contrast in social types and economic life on opposite sides of it. Yet the boundary is never a cliff and seldom even a well-defined scarp, and lowland hills are nearly as rugged and more than half as high as piedmont hills; [it] is not really a line but a zone of appreciable width; hence 'fall belt' would be a more accurate designation.1
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