|Latitude & Longitude (WGS84):||42° 3' 26'' North , 72° 7' 52'' West|
|Latitude & Longitude (decimal):||42.05722,-72.13111|
|Köppen climate type:||Dfb : Warm-summer humid continental climate|
Graphite ("black lead") was mined here by the Nipmuc to make ceremonial paints. John Winthrop the Younger (1606-1676) purchased the mine in 1644. Actual work did not begin until April 1658, and the mine seems to have been soon abandoned. Another John Winthrop, nephew of the original owner, started mining again in 1738 but ceased operations after a couple of years. There is no record of mining again until 1828-29 when Frederick Tudor (1783-1864) of Boston reopened the mine and operated it until his death in 1864. Purchased by the Massachusetts Graphite Company in 1902, it was operated occasionally until at least 1911.
Commodity ListThis is a list of exploitable or exploited mineral commodities recorded at this locality.
6 valid minerals. 1 erroneous literature entry.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
|Devonian - Silurian|
358.9 - 443.8 Ma
|Paleozoic sedimentary and volcanic rocks|
Age: Paleozoic (358.9 - 443.8 Ma)
Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. 
445.2 - 453 Ma
|Partridge Formation (includes Brimfield Schist of Emerson, 1917)|
Age: Late Ordovician (445.2 - 453 Ma)
Stratigraphic Name: Partridge Formation
Comments: Part of Bronson Hill Zone (Ordovician and Older Rocks). U-Pb zircon ages suggest that the Ammonoosuc Volcanics and tuffs of the Partridge Formation were erupted between 453 to 449 Ma, meaning they are of late Middle Ordovician and earliest Late Ordovician age. The stratigraphic relationships of these two units is very complex with current thought being that the Partridge lies between the lower and upper members of the Ammonoosuc Volcanics (Tucker and Robinson, 1990) per MA015.
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052.