1 6 NEW YORK STATE MUSEUM 



The ferruginous minerals were set free from the containing" 

 rocks by the processes of weathering and denudation which were 

 operative during a vast time interval. The Adirondack region ex- 

 isted as a land area throughout the latter part of the Precambric 

 and all of the Cambric eras. In the Lower Siluric era it was de- 

 pressed and encroached upon by the sea, but with the Taconic 

 revolution it was again upraised to remain as a land surface to the 

 present time. The weathering sufficed to break up the ferromag- 

 nesian constituents, the iron going into solution, while the magnetite 

 and pyrite were also changed more or less completely into soluble 

 compounds. Very little magnetite and none of the original pyrite 

 are found in the early sediments formed from the decay of the 

 crystallines. While it appears reasonable that the magnetite may 

 have been brought down partly as sand and subsequently altered 

 to hematite, producing the red sandstones of the Potsdam and 

 Medina formations, there is much reason for believing that the 

 Clinton ores were deposited from solution in which the iron existed 

 for the most part as ferrous carbonate but to some extent possibly 

 as sulfate. The conditions under which the ores were formed are 

 set forth more fully in a subsequent chapter. 



General structure 



The Clinton beds are uniformly inclined toward the south, the 

 direction of slope of the original coastal plain on which they were 

 deposited. Their uplift from sea level seems to have taken place 

 gradually and with little disturbance of their relative position. They 

 are nowhere displaced by faults, apparently, and only in a broad 

 way, as will be explained later, can they be said to show evidences 

 of flexure. 



The lowest dips are encountered in the central portion of tne belt,, 

 in Wayne and Cayuga counties. From the records of the deep wells 

 driven south of the outcrops, it has been possible to determine the 

 dips for this section with great exactitude. Beginning in the centra! 

 part, along the meridian of middle Wayne county, the strata have 

 an inclination amounting to 820 feet in the 18 miles from the 

 Alloway well to the outcrops on Second creek, or an average of 

 45 feet to the mile. In the 13 miles from the Clyde well to the line 

 of outcrop due north, as near as it can be located, the aggregate 

 is 640 feet or 49 feet to the mile. Between the well at Seneca 

 Falls and the Wolcott exposures, a distance of 25 miles along the 

 meridian, the average is 48 feet to the mile. From the Auburn 

 well to Sterling Station on a line slightly west of north the mean 

 dip for the 25 miles is 51 feet to the mile. 



