56 NEW YORK STATE MUSEUM 



is 73/i miles long, 3 miles wide, and includes several of the highest 

 points within the quadrangle. Being a relatively elevated mass 

 completely surrounded by faults, it is a fine example of a '* horst." 



Among other good fault ridges, though on smaller scale, are the 

 following : Grof¥-Little Cathead Alountain ridge : Buck Pond ridge ; 

 Indian Head ridge : and the ridge just west of Hamilton lake. 



A fine example of a westward tilted fault block, with steep ridge- 

 like eastern front, is the Moose-Xorth Branch mountain mass al- 

 ready described. 



Perhaps the most clearly defined of a number of fault troughs 

 is the valley at Wells. If we include with the Paleozoic rock out- 

 lier the West hill region immediately southward, we then have a 

 perfect fault basin because this whole depressed block is completely 

 bounded by faults (figure i). 



The Paleozoic rock outlier near Hope probably constitutes a fault 

 basin similar to the one at Wells, though smaller. 



The relatively depressed area between the Whitehouse and ]\loose 

 Creek faults is completely bounded by faults and is hence a fault 

 basin, being the largest within the quadrangle. 



Among other fault troughs of moderate size the best are : the 

 long depressed block just east of Fish mountain : west of Silver lake 

 outlet ; and east of Abner brook. 



On a large scale, an excellent fault trough partly within the 

 quadrangle is the great depressed block lying between the Elbow- 

 Three Ponds ^Mountain and Dewey Creek faults. The area of this 

 fault trough is about 35 square miles and is somewhat modified by 

 several intervening fractures. Figure 3 gives a good idea of the 

 character of the structure of this fault trough. 



As already suggested, the whole region lying between the Piseco 

 Lake and Hamilton Lake faults may, in a broad sense, also be re- 

 garded as a great fault trough more or less sliced by intervening 

 faults. On one side the great Panther-Potash mountain mass, and 

 on the other the Speculator-Hamilton mountain mass each rises to 

 an altitude of approximately 3000 feet, while the wide intervening 

 region is decidedly lower evidently due to the down faulting. 



Joining of faults 



A feature worthy of special mention is the general tendency of 



two faults which bound a given basin or trough actually or nearly 



to join at one end of the relatively depressed area. On a moderate 



scale this is excellently shown in the case of the \A>lls valley block. 



