13. RYE TOWNSHIP. F 2 . 305 



nearly the whole county there followed in regular succes- 

 sion the Lower Helderberg limestone and Hint shales, the 

 Oriskany sandstone, the Marcellus shale and limestone, the 

 Iron ore, the Marcellus black shale, and the Hamilton lower 

 shale amounting in all to a thickness of 600-1000 feet. But 

 in the east of Rye township this order is interrupted. The 

 Lower Helderberg limestone and shale, the Oriskany sand- 

 stone, the Marcellus shale and limestone, the Marcellus iron 

 ore, and the Marcellus black shale, and the Hamilton lower 

 shale are all absent, and the Hamilton sandstone rests di- 

 rectly upon the Onondaga red shale. 



This fact has great geological significance. The only 

 measure which we possess of the lapse of geological time in 

 Perry county is the thickness of the rocks that were de- 

 posited as that time passed by. Where the rocks are thick 

 we infer, other things being equal, that time was long ; where* 

 they are thin, the contrary. Where there are no rocks it 

 would, therefore, seem fair to infer that no time elapsed. 

 But w r e are precluded from doing this by the occurrence of 

 rocks in other townships of the county which must be placed 

 in this interval. Plate XXXIV, page 302, Fig. 2, is meant 

 to show the missing formations in Rye township : — 



In other townships. In Rye townshtp. 



Catskill. Catskill. 



Chemung. Chemung. 



Portage. Portage. 



Genessee. Genessee. 



Hamilton Upper shale. Hamilton Upper shale. 



Hamilton Lower shale, Wanting. 



Marcellus black shale, ") 



Marcellus iron ore, „. ,. 



„ > Wanting. 



Marcellus limestone, 



Marcellus shale, J 



Ijower Helderberg shale and limestone, . Wanting. 



Onondaga. 



The five bracketed together being thin, are represented 

 by one layer in the section. 



The question naturally follows : Why were these strata 

 not de|)osited in Rye township as elsewhere ? And geology 

 has but one answer : This part of the county was above sea- 

 level during some portion of that interval. This is the geo- 

 20 F\ 



