3. CENTRE TOWNSHIP. F 2 . 181 



not at once obvious how it can occupy so great an area. 

 But by studying the sections given in this report, and fol- 

 lowing them across the county along the indicated lines, the 

 puzzle will readily be solved. The 400-1'oot bed of limestone, 

 &c, has been folded and creased so sharply that its beds, as 

 there shown, are often vertical and sometimes overthrown, 

 as may be seen south of New Bloomfield at Barnett's rocks. 

 Consequently fold after fold of limestone occurs close 

 together, sometimes separated by a layer of sandstone 

 pinched into the crease and sometimes without it. The 

 limestone, therefore, extends over a much greater tract of 

 country than its mere thickness would enable it to cover, 

 and shows at the surface alternately its upper and lower 

 faces. This, too, is the cause of the recurrence of sand- 

 stone ridges parallel or rudely parallel with each other at 

 intervals of about 800 feet — double the thickness of the 

 limestone. 



Lewistown lime-shales, (No. VI.) 



These beds overlying the Lewistown limestone are ex- 

 posed in several places in Centre township, but with one 

 exception, to be noted presently, the exposures are small 

 and insignificant. The beds are seldom opened for lime be- 

 cause the more solid limestone underlying them affords it 

 at less expense and in greater purity. The small accidental 

 cuttings therefore in which these shales are displayed only 

 serve to prove the extension over the township of the fossils 

 found at the typical exposure which forms the exception 

 noted above. This exception is a roadside cutting and at 

 the same time a lime quarry which has afforded me a com- 

 plete section through the shales. It is situated about two 

 and one half miles northwest of New Bloomfield at the en- 

 trance of the gap leading through Buffalo hills to Manns- 

 ville and Ickesburg. The shales are dipping at about 30° 

 N. X. W. under the Devonian rocks and were once quarried 

 for lime, though now abandoned. 



To the section here shown all the others found in the 

 county must be referred as to a standard. No other can 

 be compared with it either in completeness or clearness. 



