86 F\ REPORT OF PROGRESS. E. W. OLAYPOLE. 



south from Mahanoy ridge to Dick's hill, with, so far as 

 can be determined, a tolerably uniform dip of about 40°. 

 Close to the northern foot of Dick's hill the Lower Helder- 

 berg limestone is quarried. Though no cutting showing 

 the shales can be seen close to the quarry, yet the surface 

 of the fields shows the presence of the Chemung sandstone ; 

 and from the color it is apparantly nearer the top than the 

 bottom of the group. Some indications also are present 

 which seem to show that the yellow shales and brown sand- 

 stones underlying the L. Helderberg limestone are brought 

 up into contact with the Chemung. 



The throw of the fault Jiere is consequently greater than 

 at any one of its western exposures, amounting, if measured 

 square across the beds, to about 4G50 feet, or vertically 6510 

 feet. 



Westward from these localities followed the fault may be 

 traced. It cuts off the Hamilton sandstone of South Furnace 

 ridge, which declines in consequence to the general level of 

 the country. This extinction of the Hamilton sandstone 

 ridge takes place about two miles southwest of the Perry 

 furnace. It cuts through the Oriskany ridge almost at the 

 point where the two outcrops are about to meet, and pass- 

 ing out of the Oriskany near the high point behind Adams' 

 Glen school-house (near Landisburg) cannot be followed 

 through the monotonous red shale of which the valley con- 

 sists. There is, however, no ground for supposing that it 

 continues into the Blue mountain, no traces of displacement 

 being visible in Kennedy's valley or on Pilot Knob. 



Eastward beyond the exposure near Montebello narrows, 

 described above, the fault continues, but its investigation 

 becomes difficult. After leaving the exposure at !No. 6, 

 which is about a mile east of the narrows, and where the 

 throw is greatest, it suddenly diminishes. The Hamilton 

 sandstone, which has been faulted up and has formed the 

 monoclinal ridge of Dick's hill, suddenly sinks and vanishes 

 underground. The land being low it is not easy to find 

 evidence <>(' its presence, but sections along the river and in 

 Watts township show that it continues to Half Falls 

 mountain. 



