251 



In the bed of the Cineiunati creek the joints are enlarged and forms 

 an underground course. The stream disappears for several hundred yards. 



The contorted layers in the Trenton Falls section are in two distinct 

 horizons. The lower one is from 4 to 6 feet thick and lies at the crest of the 

 lower part of High Fall. It outcrops also in the upper end of the gorge near 

 Prospect.. According to the measurements of Prosser and Cummmgs it lies 144 

 feet below the top of the Trenton. 



The second layer is from 8 to 15 feet thick and shown along the path oppo- 

 site High Fall and may be traced to Prospect. It lies 65 to 70 feet below the 

 top of the Trenton. 



Such contortion of strata does not appear in the outcrop of Trenton 

 exposed along Mill Creek. 



Vanuxem suggested that as the folded layer was more cyrstalline than 

 the layers above or below, the expansion of crystallization was manifested in 

 the contortion of the crystalizing layer. 



T. G. White discovered overturned fold, cross-bedded, channel filling 

 structures that must be explained by other means which would yield a con 

 siderable expansion in excess of the crystallization. 



TV. J. Miller states that it is thought that the folded structure at Trenton 

 Falls was in reality caused by a differential movement within the mass of the 

 Trenton limestone. That the whole body of the limestone has been moved 

 is clearly demonstrated by the existence of the thrust fault at Prospect. It is 

 easy to see how when the force of compression was brought to bear in the 

 region there would be a tendency for the upper Trenton beds on the upthrow 

 side to move more easily and consequently faster than the lower Trenton 

 beds. A similar explanation would apply to the lower folded zone. The folded 

 zones thus indicate horizons of weakness along which the differential move- 

 ment has taken place. As thus explained it is evident why the strike of the 

 minor folds, the strike of the fault, and the strike of the large low folds of the 

 region should be parallel, and why the contorted strata should be so local in 

 occurrence, because all the phenomena were produced by the same local 

 pressure. The differential movement would also readily account for the 

 rubbed or worn character of the upper and lower sides of the contorted zone. 



The topography of the limestone region, underlain by the Trenton. Black 

 river. Tribes Hill and Little Falls dolomite is given by E. R. Cummings, who 

 states in describing the Mohawk" valley near Amsterdam, that the lime- 

 stone region is characterized by a low, rolling relief and shallow stream val- 



