80 KEMP'S ORE DEPOSITS. 



original stringers of quartz remain following the original folds. 

 Dolomitic limestone often forms one of the walls, and still less 

 often (but especially in New England) masses of siderice are found 

 inclosed. Manganese is at times present, and in Vermont is of some 

 importance of itself. 



2.01.18. The deposits begin in Vermont, where in the vicinity 

 of Brandon they have long been ground for paint. A curious pocket 

 of lignite occurs with them and affords Tertiary fossils. This 

 prompted President Edward Hitchcock, about 1850, to refer all the 

 limonites to the Tertiary, making an instructive example of the oc- 

 casional hasty generalizations of the early days. Lignite has also 

 been found at Mont Alto, Penn. In northeastern Massachusetts, 

 at Richmond and West Stockbridge ; and just across the State line, 

 in Columbia and Dutchess counties, New York, and at Salisbury, 

 Conn., the mines are large, and were among the first worked in the 



Slate 



.Probably Limes.tpoe 



FIG. 9. Geological section of the Amenia Mine, Dutchess County, New 



York, illustrating a Siluro-Cambrian limonite deposit. After 



B. T. Putnam, Tenth Census, Vol. XV., p. 133. 



United States. The limonite forms geodes, or "pots," pipes, 

 stalactitic masses, cellular aggregates, and smaller lumps from 

 which the barren clays and ochers are removed by washing. The 

 ore is but a fraction of the material mined and occurs in irregular 

 streaks through the clays, etc. It is mostly obtained by stripping 

 and open cuts, and only rarely by underground mining, which 

 would present difficulties with such poor material for walls. 1 



1 J. D. Dana, " Occurrence and Origin of the New York and New Eng- 

 land Limonites," Amer. Jour. Sci., iii., XIV. 132, and XXVIII. 398. Rec. 

 E.Hitchcock, "Description of a Brown Coal Deposit at Brandon, Vt., 

 with an Attempt to determine the Geological Age of the Principal Ore 

 Beds of the United States," Amer. Jour. Sci., ii., XV. 95 ; Hist. Geol. 

 Survey of Vermont, I. 233. See also Lesley, below. A. L. Holley, " Notes 

 on the Salisbury (Conn.) Iron Mines and Works," M. E., VI. 220. J. P. 

 Lesley, "Mont Alto (Penn.) Lignites," Proc. Amer. Acad. Sci., 1864, 463- 

 482 ; Amer. Jour. Sci., ii., XL. 119. L. Lesquereux, " On the Fossil Fruits 

 found in Connection with the Lignite at Brandon, Vt.," Amer. Jour. Sci., 



