THE ORDOVICIAN PERIOD 



87 



disturbance has been called the 

 Taconic Revolution. In struc- 

 ture, the range consisted of a 

 series of folds, both great and 

 small, whose axes were parallel to 

 the main axis of the range, that is 

 north-northeast by south-south- 

 west. Examination of Fig. 46 

 will give the reader a good con- 

 ception of the character of the 

 folding. It is quite the rule, 

 throughout this region of Taconic 

 disturbance, to find the strata 

 either on edge or making high 

 angles with the plane of the hori- 

 zon. Many times the folds were 

 actually overturned, and in places 

 notable thrust faults were de- 

 veloped. These facts all go to 

 prove that the mountain-making 

 compressive force applied to the 

 region was of rather an extreme 

 type. Though we have no way 

 of telling just how high the range 

 may have been, nevertheless the 

 structural features and the vast 

 amount of erosion since the folds 

 were produced clearly indicate 

 that the uplift was at least some 

 thousands of feet. The Green and 

 White Mountains, Berkshire Hills, 

 Highlands of the Hudson, and the 

 Piedmont Plateau are, in a sense, 

 the remnants or roots of the great 

 Taconic Range. 



In passing westward from the 

 main axis of the range, the 

 folding is less and less intense, 

 till finally the folds die out alto- 

 gether. 



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