DESCRIPTION OF THE BESSEMER AND VANDIVER INTRODUCTION the west of the Appalachian Plateaus are the Interior Low mentary, including limestone, dolomite, conglomerate, sand­ LOCATION AND EXTENT OF THE AREA Plateaus, which are included in the Interior Plains by the stone, and shale, which have been greatly disturbed by folding United States Geological Survey but which in the opinion of and faulting, as hereinafter described. The Bessemer and Vandiver quadrangles, which are called some, including the writer, should be included in the Appala­ in this folio the Bessemer-Vandiver area, are in Jefferson and chian Highlands. SUBDIVISIONS IN ALABAMA Shelby counties in the north-central part of Alabama. (See The boundary between the Piedmont and Blue Ridge Gahaba Ridges. Although the province is in general a fig. 1.) The area is bounded by parallels 33° 15' and 33° provinces is the east foot of the Blue Ridge and the foot of valley, there are within it many high ridges that extend the high but irregular eastern scarp of the mountains of west­ parallel to its general direction, of which Red Mountain is a ern North Carolina and northern Georgia which form the good example. These ridges are generally grouped along the southern extension of the Blue Ridge. The boundary between west side of the valley from New York to Alabama. In Ala­ the Blue Ridge and Appalachian Valley provinces is the west bama the ridge section includes all the valley west of the east foot of the Blue Ridge of Virginia and of the high mountains margin of the Coosa coal field and of a line in continuation of of eastern Tennessee. This boundary continues into north­ that margin southwest through the middle of the southern part western Georgia to the point where it intersects the boundary of the Cahaba coal field. The north end of the ridge section between the Piedmont and Blue Ridge provinces, about 15 curves eastward and narrows to a point a few miles southeast miles southeast of Dalton. The Blue Ridge province thus of Gadsden. It includes Blount and Chandler mountains. terminates in northwestern Georgia. Thence south west ward The name Cahaba Ridges is here proposed for this part of the the Piedmont and Appalachian Valley provinces are contigu­ valley in Alabama. ous, the indefinite boundary between them running southwest- Birmingham Valley. The belt of relatively low land within ward through Sylacauga, Ala., to the Coastal Plain in Chilton the Cahaba Ridges lying between Shades Mountain on the County, Ala. The boundary between the Appalachian Valley southeast and Sand Mountain on the northwest and extending and the Appalachian Plateaus is, in Pennsylvania, the escarp­ the full length of the Cahaba coal field is commonly known ment known as the Allegheny Front or Allegheny Mountain; and spoken of as Birmingham Valley. It includes Shades, in southwestern Virginia and through Tennessee, the Cumber­ Jones, and Opossum valleys and Red Mountain and Enon or CHI1.TON land escarpment or Cumberland Mountain; and in Alabama, Flint Ridge. AUTAUGAJ the eastern scarp of Lookout Mountain and the eastern bound­ Coosa Valley. East of the Cahaba Ridges is the Coosa Ttaifcfllje Alabama. ary of the Warrior coal field. The western boundary of Valley, which is the broad, generally flat, low country occupied the Appalachian Plateaus through Tennessee, about midway 85° by Coosa River and its tributaries and farther southwest by between Knoxville and Nashville, is a broken escarpment 800 Cahaba River and its eastern tributaries. FIGURE 1. Index map of northeastern Alabama and portions of adjacent to 1,000 feet high, separating the Cumberland Plateau from States APPALACHIAN PLATEAUS PROVINCE The location of the Bessemer and Vandiver quadrangles, covered by Folio 821, is shown by the the Highland Rim. Northeastward the boundary, though not darker ruling. Published folios describing other quadrangles, indicated by lighter ruling, sharply defined, is extended through central Ohio to the The Appalachian Plateaus division of the Appalachian are the following: Nos. 2, Ringgold; 6, Chattanooga; 8, Sewanee; 19, Stevenson; 20, Cleve­ land ; 85, Gadsden; 78, Rome; 175, Birmingham vicinity of Cleveland. Highlands is relatively high, ranging from 500 feet above the sea, as in the Warrior coal field, to more than 4,500 feet in 30' and meridians 86° 30' and 87°. It covers one-eighth of a PIEDMONT PROVINCE Pocahontas County, W. Va., and about 2,000 feet in western square degree and has an area of 498 square miles. The area The Piedmont province is a rolling upland 1,100 feet above New York. In Tennessee it slopes somewhat westward from was surveyed in cooperation with the Geological Survey of sea level at the east foot of the Blue Ridge and 500 feet or less about 2,000 feet above sea level on the east to about 1,800 feet Alabama. above sea along the well-known " fall line," which extends on the west, where it terminates in a steep scarp 800 to 1,000 from Washington, D. C., to Columbus, Ga., through Rich­ feet high that descends to the Highland Rim of middle Ten­ EXTENT mond, Va., Raleigh, N. C., Columbia, S. C., and Augusta, Ga. nessee. The original plateau has been dissected into parts or, Its generally flat surface has been deeply trenched by the in places, obliterated by the streams that cross it so that it is Northern Alabama is in the southern part of the Appa­ streams that flow across it. It is underlain by very ancient now spoken of as a dissected plateau. One of these parts is lachian Highlands, 1 This major physiographic division of the and crumpled crystalline rocks, both igneous and metamorphic. the Cumberland Plateau of Tennessee, which is the part of the United States extends from the Atlantic Coastal Plain on the province that now most nearly answers to the conception of a BLUE RIDGE PROVINCE plateau. The high knobs of Madison and Jackson- counties The Blue Ridge province, which is narrow at its northern end are outliers of the Cumberland Plateau. in Virginia, is over 60 miles wide in North Carolina. It is a The rocks of the Appalachian Plateaus comprise sandstone, rugged region of hills and ridges and of deep, narrow valleys. conglomerate, shale, and coal. The province is in general The altitude of the higher summits in Virginia is 3,000 to coextensive with the Appalachian coal field. In contrast with 5,700 feet, and in western North Carolina Mount Mitchell, the beds of the Appalachian Valley province the strata of the 6,711 feet high, is the highest point east of Mississippi River. ' plateaus have been but slightly disturbed from their originally Throughout its extent this province stands conspicuously above horizontal attitude. the bordering provinces, from each of which it is separated by TOPOGRAPHY OF THE AREA a steep, broken, rugged front 1,000 to 3,000 feet high. The rocks of this province are closely folded quartzite, slate, GENERAL FEATURES schist, gneiss, granite, and greenstone. Nearly all of the Bessemer-Vaudiver area is in the Appa­ APPALACHIAN VALLEY PROVINCE lachian Valley province, only a few square miles in the northwest corner of the Bessemer quadrangle being in the GBHBEAL FBATORES Appalachian Plateaus. The Appalachian Valley province in The Appalachian Valley province, in the south end of the Birmingham district has two natural subdivisions named which the Bessemer-Vandiver area is situated, is a belt of the Cahaba Ridges and the Coosa Valley, which are defined country 50 to 80 miles wide, which extends from Canada into and described above. The southeast third of the Vandiver Alabama and which is on the whole lower than the Blue quadrangle falls in the Coosa Valley; the rest of the area FIGURE 2. Map of the southern part of the Appalachian province, show­ Ridge on the east and the Appalachian Plateaus on the west. except the small part in the Appalachian Plateaus lies in the ing its physiographic divisions and its relation to the Coastal Plain In the vicinity of Big Stone Gap, Va., the crest of the Big Cahaba Ridges. east to the Interior Plains on the west and from Canada and Black Mountains is 3,000 feet above the valley on the north­ The area is one of mature topography. The streams are Lake Erie on the northeast to Alabama and Georgia on the west side, and in northern Tennessee Holston Mountain, near approximately graded and reach all parts of it, so that no southwest. The boundaries of this major division, and of its the northwest front of the Blue Ridge, rises to nearly 3,000 extensive undrained surface remains. larger subdivisions are shown on the sketch map (fig. 2). feet above the valley on the southeast side. In other places, as in the Birmingham district, the valley is RELIEF not so distinctly defined by high escarpments. Nevertheless the The altitude of the area ranges from 340 feet above sea level On the grounds of differences in topography, rocks, and altitude of the limestone and shale valleys constituting the larger on Cahaba River at the south margin of the Bessemer quad­ geologic structure, the Appalachian Highlands can be divided part of the Appalachian Valley province in the Birmingham rangle to 1,520 feet on Signal Mountain, in the Vandiver into four parts called provinces. These provinces are from district is considerably lower than that of the adjacent provinces. quadrangle. Throughout most of the area the relief ranges southeast to northwest the Piedmont, the Blue Ridge, the The rocks and structural conditions that occur in the from 100 to 300 feet. The relief is notably greater, however, Appalachian Valley, and the Appalachian Plateaus. On Bessemer-Vandiver area prevail throughout the length of the near Birmingham, where the summit of Red Mountain is 400 Appalachian Valley province.