Latitude: 41°24'59"N
Longitude: 73°38'59"W
Large iron ore (magnetite) deposit discovered in 1810. Although the mine is a few miles from Brewster, it is actually in the now defunct hamlet of Tilly Foster, now partly submerged by the Middle Branch Reservoir. The official incorporated name was Tilly Foster Iron Mine. The mine was 600 feet deep in 1879. Mining ceased in 1897, after 13 miners were killed in a rockslide. The articles by Nightingale (2001) provide a historical summary and mineral details, which have been incorporated into the species info pages of this site.
It is famous for its excellent brucite, chondrodite, clinochlore, and magnetite crystals and antigorite or lizardite (and other species) pseudomorphs after a wide variety of minerals. Dana (1874), Trainer (various), and Nightingale (2001) provide details. This list below is modified from Januzzi (1976):
antigorite or lizardite after amphiboles, anhydrite, anthophyllite, fluorapatite, biotite, brucite, calcite, chondrodite, olivine, chrysotile, clinochlore, dolomite, enstatite, fluorite, magnetite, muscovite, pectolite, clinoclore, pyrrhotite, scapolite, talc
brucite after dolomite
calcite after chrysotile
dolomite after chondrodite
limonite after biotite
magnetite after chondrodite
magnetite after dolomite
pyrite after pyrrhotite
pyrrhotite after serpentine
talc after amphibole, enstatite
References
- The New York State Museum (www.nysam.org/foster/)
- Tschernich, R. (1992): Zeolites of the World, 116
- BECK, L. C. (1842) Mineralogy of New York. W. and A. White and J. Visscher, Albany, New York.
- BOURNE, W. (1957) Trip to Tilly Foster, New York. Rocks and Minerals 32, No. 5-6, 258¬260.
- BREIDENBAUGH, E. S. (1873) On the minerals found at the Tilly Foster iron mines, N.Y. Amer. Jour. Sci., series 3, 6, 207-213.
- COLONY, R. J. (1921) The magnetite iron deposits of southeastern New York. New York State Museum Bulletin, 249-250.
- COOK, G. H. (1868) The Geology of New Jersey. Newark, New Jersey.
- DANA, E. S. (1875) Preliminary notice of chondrodite crystals from the Tilly Foster mine, Brewster, New York. American Journal of Science, series 3, 9, 63-64.
- DANA, E. S. (1875b) On the chondrodite from the Tilly Foster mine, Brewster, New York. American Journal of Science, series 3, 10, 89¬103.
- DANA, J. D. (1874) On serpentine pseudo-morphs and other kinds from the Tilly Foster iron mine, Putnam County, New York. American Journal of Science, series 3, 8, 371¬381, 447-459.
- DOHERTY, E. (1934) Report on the Rocks and Minerals Association Second National Outing. Rocks and Minerals, 9, No. 7, 105
- ELWELL, W. (1936) Mineral collecting by hydroplane. Rocks and Minerals, 11, No. 6, 92 -93
- FRONDEL, C. (1970) letter to Ronald Januzzi dated January 2 1970, in reference to loss of access to the Tilly Foster mine site.
- ISACHSEN, Y. W., LANDING, E., LAUBER, J. M., RICKARD, L. V., and ROGERS, W. B., editors (1991) Geology of New York - A Simplified Account. Educational Leaflet No. 28, Albany, New York.
- JANUZZI, R. E. (1966) A Field Mineralogy of the Tilly Foster Iron Mine. Mineralogical Press
- JANUZZI, R. E. (1976) The Mineral Localities of Connecticut and Southeastern New York State. Mineralogical Press
- JANUZZI, R. E. (1989) Tilly Foster Mineral Chart. Mineralogical Press
- JANUZZI, R. E. (1994) Mineral Data Book - Western Connecticut and Environs. Mineralogical Press
- KOEBERLIN, F. R. (1909) The Brewster iron bearing district of New York. Economic Geology, 4, 713-54.
- LANDIS, E. K. (1900) The Tilly Foster mine. The Journal of the Franklin Institute, 150, 223¬226.
- LININGER, J. (1997) Iron smelting in the Hudson Highlands: a retrospective of the Greenwood Ironworks. Matrix, 5, No. 4, 146-151
- MANCHESTER, J. G. (1931) The Minerals of New York City and its Environs. New York Mineralogical Club, Bulletin Volume 3, No. 1, New York, NY, 165 p., 127 plates.
- MATHER, W. W. (1839) Third Annual Report on the Geology of the First Geological District of the State of New York. Albany, New York.
- MATHER, W. W. (1843) Geology of New York, Part I, Comprising Geology of the First Geological District. Albany, New York.
- McDOWELL, F. H. (1889) The reopening of the Tilly Foster iron-mine. Transactions of the American Institute of Mining Engineers. 17, 758-767.
- MERRILL, F.J.H. and BRITTON, N.L. (1883) Annual Report of the State Geologist for 1883. 27-77.
- MERRILL, F.J.H. and BRITTON, N.L. (1885) Annual Report of the State Geologist for 1885. 36-55.
- NIGHTINGALE, STEPHEN L. (2001): Mineral Species Reported to Occur at the Tilly Foster Iron Mine. Matrix, volume 9, no. 2, pp. 73-77.
- NIGHTINGALE, STEPHEN L. (2001): Tilly Foster Pseudomorphs. Matrix, volume 9, no. 2, pp. 78-79.
- NIGHTINGALE, STEPHEN L. (2001): The Tilly Foster Iron Mine: Southeast, Putnam County, New York. Matrix, volume 9, no. 2, pp. 51-72.
- NUWER, HENRY (1971) The Tilly Foster mine. Rocks and Minerals, 46, No. 3, 147-154.
- PELLETREAU, WILLIAM (1886) History of Putnam County, New York. W.W. Preston, Philadelphia.
- PRUCHA, JOHN J. (1956) Geology of the Brewster magnetite district of southeastern New York. New York State Museum and Science Service Circular 43.
- PUTNAM, B.T. (1886) Report on the mining industries of the United States. Tenth Census, 1880.
- ROE, A. (1990) Washington A. Roebling—his life and mineral collection. Mineralogical Record, 21, No. 1, 13-30.
- ROGERS, H. D. (1840) Final report on the geology of the State of New Jersey. 12-43.
- ROSCH, J. (1942) A Tilly Foster incident. Rocks and Minerals, 17, No. 1, 16-17
- RUTTMANN, F. S. (1887) Notes on the geology of the Tilly Foster ore-body, Putnam County, New York. Transactions of the American Institute of Mining Engineers, 15, 79- 90
- SINKANKAS, J. (1966) Gemstones of North America, Van Nostrand, Princeton, N.J. 675 p.
- SMOCK, J. C. Iron mines and iron-ore districts in the State of New York. Bulletin of the New York State Museum of Natural History, 7, 2223.
- STEWART, A. C. (1908) The magnetite belts of Putnam County, N. Y. The School of Mines Quarterly, 29, 283-294.
- TRAINER, J. N. (1938) Tilly Foster up-to-date. Rocks and Minerals, 13, No. 10, 291-303
- TRAINER, J. N. (1939) Tilly Foster up-to-date. Rocks and Minerals, 14, No. 2, 50-52
- TRAINER, J. N. (1940) Another year at Tilly Foster. Rocks and Minerals, 15, No. 4, 126 - 128
- TRAINER, J. N. (1941) The fifth year at Tilly Foster. Rocks and Minerals, 16, No. 4, 122-126
- TRAINER, J. N. (1942) Sixth year at Tilly Foster. Rocks and Minerals, 17, No. 1, 8-9
- TRAINER, J. N. (1943) More about Tilly Foster. Rocks and Minerals, 18, No. 6, 168-169
- WENDT, A. F. (1885) The iron mines of Putnam County, N. Y. Transactions of the American Institute of Mining Engineers, 13, 478- 488.
- WHITLOCK, H. P. (1903) List of New York mineral localities. Bulletin of the New York State Museum, 70, 70-7 1.
- ZODAC, P. (1934) Club and society notes. Rocks and Minerals, 9, No. 6, 91.
- ZODAC, P. (1938) Some recent finds at Tilly Foster. Rocks and Minerals, 13, No. 6, 180-181
Mineral List
116 entries listed. 91 valid minerals. 2 erroneous literature entries.
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