OUTCROPS IN GEORGIA AND ALABAMA 7S 



from the Coosa river. The White Oak Mountain area of Tennessee, 

 extending into Catoosa county, may be regarded as on the strike with 

 Taylors ridge in Catoosa, Walker, and Chattooga counties, which may be 

 taken as the westerly boundary of the Valley outcrops. The area in 

 Catoosa is insignificant, 1 to 2 miles wide, but southward its width be- 

 comes fulh^ 12 miles and the eastern edge is in Whitfield, Gordon, and 

 Floyd, or about as far toward the old land as the Chilhowie area in 

 Blount county of Tennessee. The condition observed in the White Oak 

 mountains within Tennessee becomes more marked. The Fort Payne 

 appears to be about 75 feet thick, very cherty below, and showing coarse, 

 cherty sandstones above, which Mr Hayes thinks were originally more 

 or less calcareous. The Floyd shale, synon3^mous with the Oxmoor 

 sandstone of the later Alabama reports, is mostly sandstone in the White 

 Oak mountains of Catoosa county, but mostly black carbonaceous shale 

 in Floyd and Chattooga, becoming rather more calcareous westward 

 toward Taylors ridge. A thin-bedded sandstone is in the upper portion. 

 The Floyd is from 1,350 to 850 feet, decreasing northwestwardly. The 

 Bangor is found east from Taylors ridge and 500 feet thick, so that it 

 must have extended at one time eastward into Floyd county. West- 

 ward, in Walker and Dade counties, around the northern end of Lookout 

 m_ountain and along the easterly face of Sand mountain (Waldens ridge 

 of Tennessee), the Floyd shale is wanting, the Fort Payne becomes 200 

 feet, and the Bangor 750 feet.* 



Eastern outcrops in Alabama. — From Georgia there passes into Alabama 

 the narrow strip on the east side of Lookout mountain, the broader strip 

 between Lookout and Sand mountains; from Tennessee, the Sequatchie 

 valley, known in Alabama a3 Browns valley. The earlier work by Mr 

 Hayes, which gave the structure and set forth the succession, has been 

 superseded by Mr McCalley's detailed work for the Alabama survey, so 

 that the latter must be the guide in tracing the formations through this 

 state. 



The extreme southeastern exposures are in an irregular but almost 

 continuous area, crossing Calhoun, Saint Clair, Talladega, and Shelby 

 counties, which may be regarded as lying a little farther eastward than 

 the Floyd-Gordon area of Georgia. Here the Fort Payne diminishes 

 southwardly and south westwardly, the thickness varying from 275 to 

 feet. It disappears in southern Shelby and southwestern Talladega ; 

 along the southeasterly side of the area in Calhoun it is not more than 

 25 feet ; but in Saint Clair it becomes 275 feet, and with increasing thick- 

 ness shows an increase of calcareous matter. The Bangor limestone is 



* W. C. Hayes : Geol, Survey of Alabama, Bull. no. 4, 1892, pp. 44-48 ; U. S. Geol. Survey, Ringgold 

 folio, 1894. 



