62 Bulletin of the New York State Museum. 



estimated the total production of these mines at 250,000 tons. 

 They have been idle for nearly ten years. Although the near- 

 est iron mines to New York city, they suffer the disadvantage 

 arising from high freight rates to furnaces which would otherwise 

 use them. The mines were worked early in the present century. 

 (See Am. Jour, of Science, Vol. I, p. 145.) 



We append to this section on the Limonites, of Dutchess and Col- 

 umbia counties notes, of two mines which are, apparently, isolated 

 deposits. 



ACKERMAN MINE, Mount Pleasant, Westchester County.— 

 An old opening, on a deposit of limonite, in the white, crystalline 

 limestone, which was worked many years ago, bears the above name. 

 It is on the left bank of the Saw Mill river, one mile south of Union- 

 ville. 



TOWNSEND MINE, Cornwall, Orange County.— The so-called 

 " Canterbury mine " is four miles west of Cornwall-on-Hudson and 

 near the Newburgh Short Cut E. R. It is interesting on account of 

 the geological position of the ore, in the Lower Helderberg lime- 

 stones. The mine has been idle for a decade of years. 



VII -THE CARBONATE OKE OF THE HUDSON EIVEE. 



The iron mines of the Hudson river carbonate ore are in the towns 

 of Greenport and Livingston, in Columbia county. The ore occurs in 

 beds, and in a range of hills between one and two miles east of the river 

 and east of Catskill and Linlithgo railroad stations. The outcrop is on 

 the steep, western slope, and at an elevation of 300 to 400 feet above the 

 river. The length of the outcrop, from Plass Hill, at the north, to Hart's 

 Hill south of Burden, is lour miles. Further south the strata are 

 covered by the diluvial formations of the valley of the Roelef Jan- 

 sen kill. The trend of the range is south-south-east. The ore is con- 

 formable in stratification with the underlying slates and the overlying 

 sandstones and conglomerates, and belongs apparently in the Hudson 

 River slate formation. The ore at the outcrop is everywhere more 

 or less weathered, and is of a dark-red color. On Mt. Thomas, gla- 

 cial markings were found on the ore surface, beneath the thin, earthy 

 covering. 



