COLLECTING ORDOVICIAN FOSSILS IN THE 

 SOUTHERN APPALACHIANS 



By G. ARTHUR COOPER 



Assistant Curator, Division of Stratigraphic Paleontology 

 U. S. National Museum 



The Southern Appalachians comprise a vast territory still imper- 

 fectly understood by geologists. State geological maps have been 

 prepared of Alabama, Georgia, Tennessee, and Virginia, and por- 

 tions of these States have been studied in detail. The major geologic 

 structures and the essentials of the stratigraphy are well known, 

 but no comprehensive faunal studies have ever been undertaken in 

 the Southern Appalachians. In order to facilitate studies of Ordo- 

 vician brachiopods from this region now under way, the writer spent 

 the month of May 1939 in this region with Charles Butts and Josiah 

 Bridge. Mr. Butts, while a member of the United States Geological 

 Survey, mapped the Appalachian structures and strata of Alabama 

 and Virginia. Mr. Bridge, geologist of the United States Geological 

 Survey, is now engaged in mapping parts of Tennessee. The writer 

 was thus most fortunate in having expert guidance in the field. 



Although study of the fossils of most parts of the extensive Paleo- 

 zoic column of the Southern Appalachians has been much neglected, 

 the party centered its interest on the rocks and fossils of the lower 

 Middle Ordovician. The Stones River group, or lowest part of this 

 sequence, consists almost wholly of limestone. The overlying Blount 

 group contains much shale with intercalated limestone and marble 

 beds. Above the Blount group occurs thin-bedded limestone of the 

 Black River group, which in places is red in color. In addition to 

 these groups, the black Athens shale, which is generally believed to 

 belong to the Blount group, overlies the Stones River limestone or 

 some portion of the lower Blount. It is not yet clear whether this 

 black shale is equivalent to all of the Blount group or only a part of it. 



The rocks of the Southern Appalachians occur in long northeast- 

 wardly trending belts formed by the deformation of once nearly 

 horizontal sediments. In late Pennsylvanian and Permian times the 

 rocks of this region were shoved northwestward by forces not fully 

 understood. This produced great wrinkles and shortened the earth's 

 crust many miles. Erosion has etched the wrinkles into elongate 

 ridges, of which Clinch Mountain is a conspicuous example. These 



17 



