The Tennessee Valley and Ridge section in Alabama is the southernmost section of the Valley and Ridge province of the Appalachian Highlands Region [See Figure 1]. Hereafter called the Valley and Ridge, the section is one of Alabama's five physiographic sections, each of which is recognized by its pattern of relief features and landforms that differ significantly from those of adjacent sections. The Valley and Ridge section occupies about 9 percent of the state. It occurs as a roughly northeast-trending rectangular area in central and east-central Alabama, mainly encompassing Shelby, St. Clair, Calhoun, Cherokee and parts of Jefferson, Bibb, Talladega and Etowah Counties and continues northeast into Georgia and Tennessee.

Districts
The Valley and Ridge is comprised of seven districts: Birmingham-Big Canoe Valley, Cahaba Ridge, Coosa Ridges, Cahaba Valley, Coosa Valley, Weisner Ridges, and Armuchee Ridges [See Figure 2].


The Coosa Valley is the largest of the Valley and Ridge districts. It reaches up to 23 miles wide, about 115 miles long, and runs from the Alabama-Georgia border north of Centre, in Cherokee County, to southern Shelby County, where it joins with the Cahaba Valley west of Columbiana. The western edge of the valley has formed on closely spaced thrust faults, exposing shale on the surface. The central and eastern parts of the valley formed on limestone and dolomite, predominantly of the Knox Group.
The Coosa River System
The Coosa River drains some 5,350 square miles in Alabama, most of it in the Valley and Ridge. The river enters Alabama in Cherokee County and flows southwesterly until it passes into the Piedmont physiographic section, north of Lay Lake Dam. Several main tributaries flowing from the Cumberland Plateau join the Coosa near Gadsden, including the Little River, Big Canoe Creek, Little Canoe Creek, and Big Wills Creek. The main channel ranges from 300 to 500 feet wide and is flanked in places by banks up to 25 feet in height near Gadsden. North and east of Hokes Bluff, in Etowah County, the river meanders across its own floodplain, which is about 15 miles wide. To the southwest, the valley narrows and deepens along the boundary between St. Clair and Calhoun counties, where the river cuts through the more resistant shale and sandstone of the northern edge of the Coosa Ridges district. Neeley Henry Dam is located on the Coosa at the southern edge of the ridges. To the south, the valley widens to about 20 miles across near Pell City, in St. Clair County, and the river begins to meander again. The meanders are less pronounced here because the dolomites of the Knox Group contain varying amounts of chert, and the river's meanderings are restricted by ledges of more resistant rocks along its course. Logan Martin Dam, located south of Pell City on the Coosa, was built on one of these ledges. The seven dams on the Coosa River together produce 58 percent of Alabama Power's hydroelectric power.
Natural Resources

Red Mountain iron ore was used sporadically during the Civil War, notably in the Oxmoor and Irondale furnaces but its use didn't take off until the late nineteenth century, when coke (a gray, hard, and porous material formed when coal is baked so that all the gases and volatile materials are removed) replaced charcoal as the main source of energy. In 1876, Levin Goodrich succeeded in producing pig iron using the Red Mountain Formation and coke made from local coal. Numerous coal seams, most notably the Pratt seam in the nearby Warrior basin, guaranteed a constant source of coke. Limestone and dolomite, used in iron manufacturing, were also extremely abundant in the Birmingham-Big Canoe Valley. Mining of the Red Mountain ore continued until the early 1970s, and a total of about 375 million tons of ore was removed in all.
Additional Resources
Kidd, J. T., and Shannon, S. "Stratigraphy and Structure of the Birmingham Area, Jefferson County, Alabama." Geological Society of Alabama Guidebook 16. Tuscaloosa: Geological Society of Alabama, 1978.
Additional Resources
Kidd, J. T., and Shannon, S. "Stratigraphy and Structure of the Birmingham Area, Jefferson County, Alabama." Geological Society of Alabama Guidebook 16. Tuscaloosa: Geological Society of Alabama, 1978.
White, M. L. The Birmingham District. Birmingham: Birmingham Historical Society, 1981.