286 NEW YORK STATE MUSEUM 



been beneath the sea since the close of the Utica, except for a 

 submergence of the Champ lain vallej in very recent times. In 

 all likelihood it was a depression of a channel, rather than of a 

 wide area. 



Paleozoic disturbances 



Aside from the repeated oscillations of level in the region during 

 Cambric and Siluric times, which have just been outlined, there 

 were periods of more considerable disturbance. Following Utica 

 deposition and uplift there came such a time. Compression 

 acting from the east efiEected the elevation of the Taconic range 

 with some folding and fracturing of the rocks, and in a minor 

 way the Adirondack region was affected. Again toward the close 

 of the Paleozoic the stresses which produced the folding and uplift 

 of the Appalachian region must have been felt in this region also. 

 Not unlikely there were other times of lesser stress. The effects 

 produced on the rocks of the region during these various times 

 were the same in kind, and, though the sum total of all can be 

 recognized, the relative amount to be ascribed to each period can 

 not be ascertained. The main results were the production of faults 

 and joints in the rocks.^ Minor undulations, or folds, were also 

 produced, but these are relatively insignificant and entirely sub- 

 sidiary to the other effects. The eastern Adirondack region by 

 no means felt the full force of either disturbance, and in the west 

 the effect was much less than in the east. The major line of both 

 disturbances swerves round, and approaches the region most 

 nearly at its southeast corner. 



^A fault is produced by a sliding movement of the rocks on opposite 



sides of a fissure, with the re- 

 sult that the same rock stratum 

 is higher on one side than on 

 the other, as illustrated in the 

 accompanying diagram. The 

 stratum AA has been dropped 

 on the right side of the fault 

 relative to its position on the left side. The distance ac, measured along 

 the fault plane, is called its displacement, the vertical distance ad, that 

 separates the two ends of the stratum, is called the tJiroio, and the hori- 

 zontal distance he is the Jieavc of the fault. 



