84 
' KEITH. 
Appalachians have been distorted after their production, 
and in them the folding is very rarely great. Here, how¬ 
ever, it is carried even to overturning, as shown south of 
section G. As this fold has the full amount of Appalachian 
deformation and ordinary faults were developed during its 
later stages, then this plane of discordance must have pre¬ 
ceded the recognized Appalachian folding, if it be a fault, 
and have resulted from a previous period of deformation. 
Hence a special period of disturbance must be assumed, if 
this discordance be considered a fault, and of this new period 
we have no other evidence. 
(2) Another difference between fault planes and this con¬ 
tact is illustrated in the transition previously described south 
of section G. In that locality the bottom bed of the lime¬ 
stone series, a calcareous slate, contains fragments of the 
quartzite. The same feature appears on the opposite or 
northwest side of the cove, where there are outcrops of a 
breccia of sandstone and chert at the contact of the lime¬ 
stone and the Chilhowee sandstone. 
(3) To sum up, the mere discordance along the plane of 
contact is common to the three hypotheses and decisive of 
neither. The well developed folding of the plane, if it is a 
fault, necessitates the assumption of a new and unrecorded 
period of deformation. The irregularities of the plane ex¬ 
ceed those of faults. The fragments of sandstone can only 
be introduced into the limestone during the process of sedi¬ 
mentation. For these reasons the hypothesis of faulting 
seems inadequate to explain the discordance. 
VI. (c) The hypothesis of erosion'and unconformable depo¬ 
sition remains, therefore, as the only explanation of the ob¬ 
served discordance. Negatively it is the explanation, because 
other possible ones are inadequate; positively it is, because 
certain features of the contact can only be produced by sedi¬ 
mentation. These features are the inclusion of fragments of 
lower rocks in beds above the plane of discordance and the 
presence of limestone in ravines in the Chilhowee sandstone. 
This explanation is corroborated by the existence of uncoil- 
