|Latitude & Longitude (WGS84):||41° 27' 14'' North , 72° 30' 25'' West|
|Latitude & Longitude (decimal):||41.45389,-72.50694|
|Köppen climate type:||Cfa : Humid subtropical climate|
The west side of Long Hill is host to a quartz crystal deposit where a fault apparently cross-cuts the thin layer of quartzite shown there on the bedrock map of the Haddam quadrangle. These crystals are similar in habit to those found at West Stafford and Moosup, Connecticut, where Mesozoic faults have brecciated quartzite.
It was known as far back as 1825 because it appears on the sketch map by Porter (1825). Williams (1899 and circa 1945) described the locality and crystals accurately: "On the west side of Longhill Quartz crystals can be dug by the bushel.", "in size they are from an inch to ten inches in length often aggregated laterally into groups."
Davis (1901) states: "well defined crystals of large size, translucent, and slightly discolored by oxide of iron, are found loose in the soil. Many of the smaller crystals are doubly terminated and perfectly transparent.
Location is very approximate.
1 valid mineral.
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. 
|Middle Ordovician - Early Ordovician|
458.4 - 485.4 Ma
Age: Ordovician (458.4 - 485.4 Ma)
Stratigraphic Name: Monson Gneiss
Description: (May be equivalent to part of Waterford Group) - Interlayered light to dark, mostly medium to coarse-grained gneiss and amphibolite; gneiss composed of plagioclase, quartz, and biotite, with hornblende in some layers and microcline in others; traces of garnet, epidote, and magnetite.
Comments: Part of Eastern Uplands; Iapetus (Oceanic) Terrane - Bronson Hill Anticlinorium. Swanzey, Pauchaug, Monson, and Fourmile Gneisses represent metamorphosed intrusive igneous rocks and yield ages from 454 to 442+3/-2 Ma. Therefore, ages range from early Late through latest Ordovician. Authors suggest that they represent the plutonic root of a calc-alkaline magmatic arc at least 250 km long that was produced partly or entirely on a continental margin in the Late Ordovician. The overlying Ammonoosuc Volcanics and Partridge Formation, rather that resting unconformably on these plagioclase-rich plutonic gneiss, are now known to have had a magmatic history overlapping with them and are approximately the same age (Tucker and Robinson, 1990) per CT012.
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.