﻿114 NEW YORK STATE MUSEUM 



In addition to the evidence which the general stratigraphy of the 

 region furnishes as to the early date of some of this warping, evi- 

 dence which has been already set forth, it also appears that the 

 Potsdam and Theresa formations are somewhat more folded than 

 are the overlying limestones, implying that they, were somewhat 

 folded prior to the deposition of the limestones. This is best 

 shown in the district southwest from Clayton, along the valley of 

 French creek, where the Potsdam is arched up into a prominent 

 dome, even to the extent of bringing up the Precambric. The 

 dome falls away to the south with rather steep dip, there is scant 

 room for the Theresa formation between the south margin of Pots- 

 dam outcrop and the Pamelia front just beyond, and this Pamelia 

 inface passes across the line of prolongation of this fold to the 

 south yet shows no sign of being affected by it, being precisely 

 the same . cliff of horizontal limestone that it is to the east and 

 west of this line. It is of course possible that a fault lies between, 

 but the faults of the district are infrequent and insignificant, so far 

 as known, so that the supposition seems unlikely, and the evidence 

 seems to clearly point to folding and subsequent wear, during the 

 long time interval between the close of Theresa and the beginning of 

 Pamelia deposition. Evidence of less distinctive character but of 

 the same kind is also forthcoming elsewhere. 



Two series of low folds intersecting at right angles result in pro- 

 ducing maxima of elevation at the intersections of arches and of 

 depression at trough intersections, with intermediate conditions 

 where trough of one set meets arch of the other. In other words 

 the axes of the north-south folds are themselves folded by the east- 

 west folds, producing elevated domes along the arches, and depressed 

 basins along the troughs. A prominent feature of the areal maps is 

 the considerable number of outliers and inliers of the various forma- 

 tions there shown. 1 The abundant Potsdam outliers on the Pre- 

 cambric are more largely due to the irregularity of the floor on which 

 the formation was laid down, than to the. subsequent folding. But 



1 Along the southern margin of the Theresa sheet are shown a number 

 of patches of Leray limestone, lying to the north of the main line of 

 outcrop of the formation, and entirely surrounded by the older Lowville 

 limestone. The Leray limestone formerly extended over the entire dis- 

 trict, and has been worn away from much of it, these representing out- 

 lying patches or residuals left behind in this general process of removal, 

 hence known as outliers. Inliers on the other hand are patches of an older 

 rock entirely surrounded by a younger, such as the Precambric by French 

 creek south of Clayton, or the Lowville near Threemile Bay and Three- 

 mile Bay creek, on the Clayton sheet. These are much less common than 

 outliers and are strongly indicative of a warped upper surface' of the 

 formation constituting the inlier. 



