66 F*. REPORT OF PROGRESS. B. W. CLAY POLK. 



No, VIII c. Hamilton group. 

 The Eamilton group in Perry county consists of a great 

 mass of strata comprehending almost all kinds of sedi- 

 mentary material. The following section represents its 

 general components and dimensions including the Mar- 

 cellus : 



Hamilton Upper Shale, 200'— 300' j 



Hamilton (Montebello) sandstone, 500'— 800' ? Average, 900' 



Hamilton Lower Shale, 400— 500' ) 



5. Marcellus Black Shale, 80'— 120' 



4. Marcellus Iron Ore, 2'— 14' 



3. Marcellus Limestone, 10'— 40' 



2. Marcellus Lime Shale, 20'— 40' 



1. Marcellus Lower Ore, 2— 3' 



Oriskany Sandstone. 



The Hamilton lower shale. 



The lower shales of the Hamilton group consist of about 

 500 feet of olive sandy shale often with interbedded thin 

 sandstones of the same color. They are generally much 

 stained with iron toward the lower portion, sometimes con- 

 taining thin layers of poor hematite. Downward they grad- 

 uate imperceptibly into the upper beds of the Marcellus, 

 growing darker and darker. Upwards they pass as imper- 

 ceptibly into the basal beds of the Hamilton sandstone, be- 

 coming more and more sandy until solid sandstone ensues. 

 Their thickness is very constant, apparently greater in the 

 northwest ; and they extend over the whole county except 

 the small district on the southeast described in the report 

 on Rye township. 



These shales are soft and their disintegration has in part 

 produced the broad valleys that usually run along between 

 tin* ridge <>1' Hamilton sandstone and those of the Oriskany, 

 if the Latter is hard enough to form one; if not, the val- 

 ley eroded in the Lower Hamilton shales blends with that 

 of the Marcellus, Oriskany and the upper part of the Lower 

 Helderberg. 



The soil produced by the disintegration of these shales is 

 lean and poor, and easily distinguishable by its whitish 

 hue. In some places it extends over considerable areas, as 

 ai the west end of Dick's hill, about Little Germany, and 



