3. CENTRE TOWNSHIP. F*. 197 



The Hamilton lower shale. 



Lying immediately over the black Marcellus shale come 

 the Lower Hamilton shales, softer and lighter in color. 

 They run through the township, following very closely the 

 line of outcrop of the Hamilton sandstone which overlies 

 them. The latter forms the ridges the former the valley. 

 Unable on account of its softness to resist the weather as 

 the hard stone has done, it has been eroded by frost, sun- 

 shine, and rain, and now forms valleys alongside of the 

 harder rocks. The northern slope of Mahanoy ridge and 

 the southern slope of Buffalo hills are composed of the 

 Hamilton lower shales, covered very deeply by the wreck- 

 age from the overhanging Hamilton sandstone. The slope 

 at the western end of Dick's hill also consists of these shales 

 rising from under the heavy sandstone. It extends in long 

 tongues west into Iron ridge, and is gradually thrown out 

 by the rising of the older limestone to the surface. 



Xo other outcrop of the Hamilton lower shales exists in 

 Centre county, and in these the exposure of bed rock is rare. 

 In only one or two places in the gaps or passes as on Dor- 

 ran s run and at the old Juniata furnace can the low r er shales 

 be studied in x^lace. 



Fossils — These shales are exceedingly barren, frequent 

 and careful search at all the outcrops in the township hav- 

 ing failed to bring to light any fossils. Either life in the 

 ocean of this age was scarce in Centre township or all traces 

 of its exisience have been destroyed. 



Land. — The Lower Hamilton shales yield mostly poor 

 land, inferior to that over the other shales of the township, 

 (rood farming and free expenditure of labor can, however, 

 render it fairly })roductive and in the end profitable. 



The Hamilton sandstone. 



This is the most conspicuous feature in the physiography 

 of ( -litre township. The Lower Helderberg limestone forms 

 a high ridge, but most of it is under cultivation, and more 

 of it would be tilled were it not for the numerous sinkholes 

 on its surface. The Oriskany sandstone in many places 



