FAULTING AND UNCONFORMABLE DEPOSTION. 181 



The structure of Price mountain was quite carefully studied by the 

 writer, and but two explanations seemed at all applicable to account for 

 the present anomalous structure. 



Its Formation by Faulting discussed. — The phenomena described can 

 be accounted for by faulting in only one way, and that is by a broad, 

 flat overthrust, such as are common in the extreme southern Appa- 

 lachian and have been described before this society by C. W. Hayes.* In 

 such a case it is reasonable to conclude that, in common with all such 

 known overthrusts, the mass overthrust must have come from the south- 

 east ; but from where in the southeast could such a mass have come ? 

 This is the last known exposure of these rocks in that direction, and it 

 is difficult to conceive from whence this mass could have been thrust 

 Again, while it is just possible that in an overthrust of this kind one 

 horizon only of the overthrust mass should come in contact with the 

 strata underneath, it is decidedly improbable and certainly militates 

 against such an origin. Lastly, the contact phenomena, as far as they 

 were observed, do not resemble fault phenomena, for in this type of 

 faulting there are generally places where the different rocks can be seen 

 in close proximity if not in actual contact, and in all such cases the 

 formations in contact, if they be soft and yielding beds, show great con- 

 tortion. This should be especially marked in this case, for the over- 

 lying beds are very soft, and a thrust of this extent must necessarily 

 have crumpled them very much ; yet the red shales are perfectly regular 

 and show no greater dip nor greater irregularity near the line of uncon- 

 formity than in the interior of the area. At the only point where the 

 beds near the line of contact were seen the red shales had the regular 

 outward dip due to the anticlinal fold, but the limestones beneath were 

 much contorted, due probably to earlier folding. 



The condition of the coal-beds in Price mountain as described by 

 Fontaine is still further evidence against faulting of any kind, for if 

 such violent overthrusts as are required to produce this structure had 

 actually occurred, the softer members of the series would have certainly 

 shown some effects of the force. An isolated mass like Price mountain, 

 thrust into its present position, would have suffered much worse than 

 Brushy mountain, which is simply a portion of a faulted syncline. Al- 

 together the evidence does not seem to sustain the theory of faulting 

 unless the conditions attending the faulting were almost abnormal and 

 decidedly improbable. 



Its Formation by unconformable Deposition discussed. — The peculiar 

 relation of the sandstones and shales of Price mountain to the adjacent 

 limestone suggests the possibility of an overlap of these Lower Carbonif- 



* Overthrust Faults of the Southern Appalachian, Bull. Geal. Soc. of Am., vol. 2, pp. 141-154. 



