676 MAR J us R. CAMPBELL 



Examples may be multiplied indefinitely, but enough has 

 been cited to show that Appalachian drainage has all of the 

 marks which theoretically we should expect to find on a tilted 

 surface. 



(5) VERY REMOTE CHANGES SHOWN IN SOME OF THE APPALACHIAN 



RIVERS. 



In passing still farther backward in geologic time, the minor 

 drainage ceases to be our guide ; and we are limited to the big 

 trunk streams from which to read the history of events. Almost 

 every large stream of the Appalachians gives some hint of the 

 surface conditions under which it was formed. 



(^) Chattahoochee drai?iage line. — The limits of this paper will 

 not permit the mention of all the probable examples, only a few 

 of the most striking will be given. Perhaps the most pro- 

 nounced example of the kind, and at the same time one that 

 carries the history back the farthest, is that of a series of 

 streams on the eastern side of the Blue Ridge, the arrangement 

 of which appears to have been determined by the depression 

 which preceded and made possible the deposition of the Triassic 

 sediments of the eastern part of the United States. A glance at 

 a map reveals the fact that the course of the Chattahoochee 

 River above Columbus, Georgia ; the Savannah above Tallulah 

 Falls; the French Broad above Asheville ; and the upper por- 

 tions of the Catawba and Yadkin rivers occupy almost continu- 

 ously a line from the margin of the Cretaceous sediments of the 

 Gulf coast to the Triassic deposits of the Dan River area. This 

 continuity of drainage lines at once suggests some common 

 cause, for it seems highly improbable that their location along 

 this line was simply fortuitous. According to the principles 

 laid down in the preceding parts of this paper, such an arrange- 

 ment could have been brought about by a subsidence the axis of 

 which corresponds with the present drainage lines. 



{b^ Triassic areas in the same luie. — The areas of Triassic 

 rocks in this region are generally regarded as remnants of a 

 more extended deposit which took place in troughs formed by 



