ABSTRACT

The pre-Mississippian rocks of the Warrior basin in Alabama consist of thick Cambrian through Devonian carbonates with lesser amounts of clastics. A recent wildcat well in Cullman County, Alabama has revealed the nature of the basement complex. Above the basement, the Cullman County wildcat penetrated three Cambrian units previously undescribed from the Warrior basin, in addition to penetrating the entire Knox. The top of the Knox in parts of the Warrior basin has been questioned by past workers who have failed to agree on a common pick. The post-Knox Ordovician, as defined by the writer, consists of two major lithologic units traceable in the subsurface of Alabama; a lower unit correlative with the Stones River Group of north Alabama and Tennessee and an upper phosphatic limestone unit that pinches out in the southern parts of the Warrior basin in Alabama. The Silurian consists predominantly of greenish-gray and grayish-red carbonate and clastic units that thin to the north and southwest and attain a maximum thickness in Tuscaloosa and Jefferson counties. The Devonian carbonate section as defined thins rapidly to the northeast and is absent in most of central and northern Alabama where the Devonian is represented only by the Chattanooga Shale.