REPORT OF THE DIRECTOR I914 21 



great thrust plane is evident in Bald mountain, just across the river 

 from where this volcano lies. All these folds have been thrust from 

 the east westward. There is, then, the large possibility that this 

 volcanic plug has been cut across by such a thrust fault and has 

 been transported from its original place eastward on the thrusted 

 portion of the fold. If this is true, the rest of the plug is somew^here 

 to the east, perhaps over the state line in Vermont, buried out of 

 present view. Thus some geologists think; others conceive that 

 the lava came up where it is during the Devonic period, like the 

 volcanic hills which dot the St Lawrence plain north of the state 

 boundary, and penetrated overlying rocks now worn away. But 

 whatever the truth, the volcano is a problem still of great geological 

 interest and the effort to save it is timely for the attacks upon it 

 have carried off a substantial part of it, though leaving its present 

 exposure most instructive. 



THE CLARK RESERVATION 



A glacial park 



In the course of the operations of the Geological Survey, the 

 study of the water courses resulting from the melting of the great 

 ice sheet brought into prominence the abandoned gorges and cata- 

 ract cliffs of the great east and west glacial streams which cut 

 through the rock beds of the Helderberg plateau in the region 

 lying to the southeast of Syracuse and both east and west of the 

 village of Jamesville. These great streams were made while the 

 ice was extending, in retreat, over the basin of Lake Ontario and 

 the valley of the St Lawrence river, and the discharge of these 

 streams was from the west toward the east along the commanding 

 front of the ice sheet and out into the Mohawk-Hudson drainage. 

 The present drainage of this region is by streams which flow from 

 south to north and the old abandoned waterways transect these 

 existing drainage features. 



The features presented in this region are extraordinary in more 

 than one sense. They are highly picturesque and their record is 

 that of a great body of flowing water larger than Niagara which 

 made one cataract at least of horse-shoe shape higher than the 

 Horseshoe Falls of Niagara, and the whole strip of country is dotted 

 with the abandoned plunge-basins of subsidiary falls with potholes 

 and the rocky ravines of contributory gorges. 



Most conspicuous among these abandoned escarpments is that 

 which surrounds the Jamesville lake and over which a cataract 



