McGee — Southern Extension of Appomattox Formation. 19 



Appalachian deformation ; it tells of profound depression, 

 pronounced seaward tilting, and prolonged submergence of the 

 young continent, whereby preexistent physiography was greatly 

 modified, the cis-Mississippi land shrinking to half its area with 

 such attendant climatal changes that the fauna of land and sea 

 was changed and the land flora revolutionized more completely 

 than in any other eon of the earth's history ; yet the record of 

 the formation is so readily susceptible of interpretation that, 

 despite the remoteness of the period, and despite the obscurity 

 of later records, it is already possible to map with approximate 

 accuracy the geography of the Potomac epoch. So the forma- 

 tion is a structural and chronologic unit from which the strati- 

 graphy and the geological history of the Coastal Plain may be 

 reckoned. 



General Characters and Relations. 



As exposed north of Roanoke river, the Appomattox forma- 

 tion consists of moderately regularly stratified sand or clay, 

 with occasional intercalations of fine gravel, commonly of 

 pronounced orange hue, and without fossils so far as known. 

 Farther southward these characters are generally maintained ; 

 but local variations appear from place to place, and certain 

 other moderately constant features are displayed. 



In eastern-central North Carolina the formation is notably 

 variable and heterogeneous over the thinly covered eastern 

 extension of the Piedmont crystallines now culminating in the 

 continental projection of Cape Hatteras, (which has been during 

 past ages an even more conspicuous geographic feature than 

 to-day); and its features are evidently connected with the 

 proximity of the crystalline strata. Thus, at Wilson there is 

 the usual partition into several regular and rather heavy (2 to 

 5 feet) strata, the usual orange hue, and the usual distribution 

 of quartzite and quartz pebbles either throughout the several 

 strata or in bands or pockets ; but the lowermost stratum 

 exposed in the northern part of town is largely composed of 

 arkose, slightly rearranged and sparsely intermixed with fine 

 quartz pebbles ; and there is some admixture of arkose in the 

 superior layers. Then, half a mile south of Wilson, a nine-foot 

 railway cutting displays the usual heavy and moderately regular 

 bedding, and the usual hues both in weathered and unweathered 

 strata ; while the lowest exposed bed (4 or 5 feet thick) is made 

 up of inter-laminated gray or white clay and orange or reddish 

 loam, the clay being fine and plastic, the loam rather sandy and 

 massive within each lamina, and the laminae sensibly horizontal 

 and ranging from an eighth of an inch to half an inch thick for 

 the clay, and quarter of an inch to an inch or more for the loam. 

 Both of these exceptional aspects of the formation are exhibited 



