IRON ORES OF THE CLINTON FORMATION 



II 



GENERAL GEOLOGY 



Stratigraphic relations of the Clinton formation 



The Clinton formation falls within the middle division of the 

 Upper Siluric or Ontario system. At the base of this system, as con- 

 stituted in New York, lies the Oswegan group which includes the 

 Medina and Oswego sandstones and the Oneida conglomerate. The 

 middle or Niagaran group consists of the Clinton at the base, fol- 

 lowed by the Rochester shale and the Lockport and Guelph dolo- 

 mites. The upper or Cayugan group is made up, in ascending order, 

 of the Salina, Cobleskill, Rondout and Manlius formations. The 

 succession is shown in the following table : 



ERA OR SYSTEM 



Ontario 

 or 

 Upper Siluric 



J 



PERIOD OR GROUP 



Cayugan 



Niagaran 



Oswegan 



AGE OR STAGE 



f Manlius limestone 

 Rondout waterlime 

 Cobleskill limestone 

 Salina beds 



' Guelph dolomite 

 Lockport dolomite 

 Rochester shale 

 Clinton beds 



including 



Medina sandstone, 



the Oswego sandstone and 

 Oneida conglomerate 



In tracing the Upper Siluric formations across the State it has 

 been found that the higher members have a greater linear extent than 

 the lower ones. This is due to a progressive overlap in sedimenta- 

 tion, whereby each member has had a wider area of deposition 

 than the one immediately preceding. The general relations will be 

 readily understood from the accompanying diagram. It will be ob- 

 served that there is one exception to the statement above in regard 



