344 F a . REPORT OF PROGRESS. K. W. CLAYPOLE. 



tained from these lower shales in the county. One bed ap- 

 parently abounded in its remains, which were strewn over 

 the ground by the action of the weather. 



The Hamilton sandstone, ( VIII.) 



The Hamilton sandstone is the factor of the most con- 

 spicuous though not perhaps of the most useful features of 

 Spring township. Its hard beds cropping out across the 

 synclinal axis of southern Perry county enclose an angle in 

 the south of the township which is thus, except by one gap, 

 almost cut off from communication with the rest. Mount 

 Pisgah, at the angle of the syncline, rises high and bold, 

 and is a prominent object for miles around. The rest of the 

 range in the township is not high, but rough and steep 

 on the side toward Sherman's creek, owing to the great 

 hardness and solidity of the Hamilton sandstone. Little 

 mountain is so named only by contrast with the Blue 

 mountains, its greater neighbor. It would hardly have re- 

 ceived the name had the latter not been so near. The 

 Hamilton sandstone is so thick and solid that its outcrop 

 forms a ridge comparable in height and mass with that of 

 the Blue mountains themselves. 



Farther north the South Furnace hill enters from Centre, 

 and would form another sandstone wall in the township 

 near its middle, were it not cut out by the fault which 

 crosses the syncline, gradually thinning down to nothing 

 the outcrop of the sandstone, and consequently lowering to 

 nothing the altitude of the ridge. Continuing eastward this 

 ridge turns round the end of the anticline, runs westward 

 at the North Furnace hill, which continues in a straight 

 line until it gradually approaches and at last unites with the 

 monoclinal west end of Crawley hill, both forming on the 

 east side of Beggar's run a single wooded synclinal ridge. 



The long outcrop of the Hamilton sandstone forming 

 Mahanoy ridge is partly in Spring township. Coming in 

 from Centre it ranges west nearly to Little Germany, where 

 it terminates in a high synclinal knob. Returning eastward 

 the line of outcrop encounters the fault running along this 

 valley and is cul completely through, the severed end being 



