20 NEW YORK STATE MUSEUM 



within the schists and the sandstone is entirely absent. Again the 

 existence of a pecuHar rock resembling serpentine, in masses not 

 unlike dikes has been emphasized by writers who would refer the 

 ores to igneous sources, as it is known that serpentine generally 

 owes its origin to alteration of basic intrusives. Still another ex- 

 planation is based on the fact that bands of pyritic schist are found 

 in close association with the deposits and involve the oxidation of. 

 the pyrite and replacement of the limestone by the resulting iron 

 oxids. While the present work has not been carried sufficiently 

 far to warrant, as yet, a statement of the results in reference to the 

 relations and origin of the ores, it is believed that a comprehensive 

 investigation of the field, which has never before been undertaken, 

 will throw much new light on these interesting problems. 



Field work on the Clinton hematite ores was undertaken by the 

 Assistant in Economic Geology for the purpose of ascertaining 

 more definitely the stratigraphic relations, areal distribution, 

 variations in character and thickness of the deposits on different 

 meridional sections along the outcrop. 



In passing eastward from Niagara Falls, the Clinton ore is first 

 encountered near Rochester where the bed has a thickness of 14 

 inches. The ore here rests on beds of green shale 24 feet thick, 

 while the overlying formation is a hard limestone 14 feet in thick- 

 ness. The same stratigraphic relations are found at Ontario, 

 Wayne co., 17 miles east of Rochester, where the ore measures 22 

 inches. Mining operations have been conducted in that vicinity for 

 many years and the line of workings extends about 5 miles, from a 

 little north of Ontario village westward to Union Hill, near the 

 Wayne-Monroe county line. The Furnaceville Iron Co. is now 

 engaged in mining ore on its property just north of Ontario Center. 

 The methods employed by the company, which consist briefly in the 

 excavation of long trenches parallel to the line of outcrop, are 

 economical and well adapted to the work. About 20 feet of soil 

 and rock have to be removed before taking out the ore, steam 

 shovels and derricks being used for the purpose. 



The Clinton ore was formerly mined near Wolcott, 25 miles east 

 of Ontario. A furnace was in blast here as early as 1834, but has 

 not been in operation since 1879. The ore was obtained at a 

 locality 4 miles east of the furnace where the bed is said to be 30 

 inches thick, with 20 feet of overburden. The mines are now inac- 

 cessible. Some ore was obtained also along Wolcott creek just 

 below the furnace. The bed is here 14 inches thick, but as it lies 



