13. RYE TOWNSHIP. F\ 309 



township report, each of those beds successively overlaps 

 that below it until the last — the Hamilton lower shale — 

 almost, and perhaps quite, reaches the southeastern part of 

 the township, though if it there exists it is exceedingly thin. 

 This regular overlap indicates their deposition against a sub- 

 siding shore, up which they rose successively higher and 

 higher until at length the land sank below the sea level and 

 the Hamilton sandstone was deposited over all. 

 . The Lower Helderberg limestone as shown on the map 

 thins away eastward from Oak Grove Furnace until it totally 

 disappears before reaching Sterrett 7 s gap. The conspicuous 

 ridge which it forms in Carroll township gradually sinks 

 until no trace of it can be seen. # But the Lower Helderberg 

 group can be traced by its Hint beds nearly to the gap, and 

 about the same place the last relics of the Oriskany sand- 

 stone appear. Careful examination shows that the lower 

 beds of the limestone are first lost, and the highest, the 

 flint-beds, persist farthest. Beyond these, eastward, the 

 Lower Hamilton shale alone exists. All these rocks were 

 consequently deposited during submergence, and for this 

 reason the destruction of the upper part of the Onondaga 

 shale was given above as the only memorial of the period 

 of elevation. 



This subsidence bringing the whole township again below 

 the sea, and amounting to about 1000 feet, measured by the 

 thickness of the missing beds was not improbably the means 

 of so changing the drainage of the adjoining district as to 

 bring on the next stage in the history of the township. 



After this temporary emergence, Rye township sank 

 again beneath the waters, and over its whole surface was 

 laid down the massive bed of Hamilton sandstone, here 800 

 feet thick. This deposit indicates another important change 

 in the history of the district. The Hamilton sandstone is 

 a formation peculiar to this j>art of the State. The Hamil- 

 ton group in New York and in Northern Pennsylvania con- 

 sists entirely of soft material, shales and thin sandstones, 

 the latter not abundant. But in Perry and the adjoining 

 counties there is interbedded witli these shales a heavy, 

 hard, coarse sandstone spread out like a fan and thickening 



