

3. CENTRE TOWNSHIP. F\ 201 



sesses none of the beauty of those through the Buffalo hills, 

 being occupied almost wholly by the road, the stream, and 

 the mill-race. 



The second gap about a mile to the eastward also gives 

 passage to a small stream flowing from several ample springs 

 in the valley, one on the farm of Mr. Oliver Rice and an- 

 other on that of Mr. R. Moore. Its course consequently is 

 short but it supplies power to two mills in the narrows. In 

 physical features this gap resembles those in the north of 

 the township but both the gaps in Mahanoy ridge are short 

 compared with those in the Buffalo range. The geological 

 cause of this is obvious. The Hamilton sandstone in the 

 former stands almost vertical whereas in the latter it dips 

 at an angle of about 30° to the north. Consequently in the 

 former the thickness of the formation — about 600 feet — 

 measures the breadth of the ridge and the length of the 

 gap while in the former owing to the angle of dip these 

 measurements are doubled. (See Plate XVII, page 178, 

 Fig. 4.) 



Both the ridges, as may be seen from the diagram, are 

 monoclinal or one-sided, the intervening portion of the arch 

 represented by dotted lines having been swept away. 



The third outcrop of the Hamilton sandstone in Centre 

 township is the eastern end of Crawley hill, the western 

 part of which is in Spring township, and forms a high 

 rough ridge parallel with Mahanoy, and distant only about 

 half a mile. Between them runs the Little Germany fault. 



The hard middle beds of the Hamilton sandstone are well 

 exposed on the top of Crawley hill, and flagstones of fair 

 quality are sometimes quarried here for curbing. The ridge 

 rises abruptly from the south side of the road from New 

 Bloomfield to Little Germany, and the valley cut in the 

 Hamilton upper shale and Genessee becomes narrower and 

 narrower towards the west. This ridge differs in structure 

 from those already described, being an anticlinal or arch, as 

 maybe seen by examining the sections through the county. 



A fourth outcrop of Hamilton sandstone occurs imme- 

 diately south of the last, but, so far as \ have been able to 

 learn, has no distinctive name. Its most eastern point is 



