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Geologic Unit: Mendon

Publication:
Whittle, C.L., 1894, The occurrence of Algonkian rocks in Vermont 
   and the evidence for their subdivision: Journal of Geology, 
   v. 2, p. 396-429.
Usage in Publication:
Mendon series

Modifications: Geologic Province: Dominant Lithology:
 Named
 New England province
 Schist
 Quartzite
 Conglomerate
 Limestone

Summary:
Named for good exposures in town of Mendon, 1 mi south of Mendon Village, Rutland Co., southwestern VT. Consists of more or less metamorphosed clastic rocks of sedimentary origin [conglomerate, arkose, quartzite, calcite, marble, dolomite, calcareous schist, biotite schist, chlorite schist, actinolite schist, tourmalinized schist, and gneiss]. Thickness ranges from 200 to 2,000 ft. Overlies Mount Holly gneiss; unconformably(?) underlies Lower Cambrian quartzite. Age is Precambrian (Algonkian).
Source: GNU records (USGS DDS-6; Reston GNULEX).


Publication:
Prindle, L.M., and Knopf, E.B., 1932, Geology of the Taconic 
   quadrangle: American Journal of Science, 5th series, v. 24, 
   p. 257-302.
Usage in Publication:
Mendon schist*

Modifications: Geologic Province: Dominant Lithology:
 Revised
 New England province
 

Summary:
Because rocks of the Mendon series are predominantly schist, the name is changed to Mendon schist. Does contain some limestone and dolomite.
Source: GNU records (USGS DDS-6; Reston GNULEX).


Publication:
Osberg, P.H., 1952, The Green Mountain anticlinorium in the 
   vicinity of Rochester and East Middlebury, Vermont: Vermont 
   Geological Survey Bulletin, no. 5, 127 p.
Usage in Publication:
Mendon formation

Modifications: Geologic Province: Dominant Lithology:
 Revised
 Age modified
 New England province
 

Summary:
Mendon series revised as Mendon formation to conform with present stratigraphic usage. Crops out along upper part of western escarpment of Green Mountains and underlies summit and eastern slopes of Mount Moosalamoo. Also underlies area between Chandler Ridge and Romance Mountain. Pebbly crystalline limestone member mapped by Whittle (1894) is here referred to as Forestdale member [rank reduced from Forestdale marble of Keith (1932)]. Mica schist member mapped by Whittle (1894) is here referred to as Moosalamoo member [rank reduced from Moosalamoo phyllite of Keith (1932)]. Forestdale is 600 ft above base of Mendon; Moosalamoo is lenticular body in upper part of Mendon. Thickness of Mendon is 800 to 1,800 ft. Underlies Cheshire quartzite. Age changed to Early Cambrian based on work of Prindle and Knopf (1932) who cite OLENELLUS in quartzite above rocks known to be Precambrian. Micaceous phyllite overlies quartzite and is in turn overlain by more quartzite. This relationship is seen in Moosalamoo member and Cheshire quartzite in Rochester-East Middlebury, VT, area. If this interpretation is correct, beds of quartzite containing OLENELLUS underlie equivalent of Moosalamoo and therefore must represent quartzites interbedded with equivalent of lower part of Mendon formation. This implies that rocks below Cheshire quartzite and above Precambrian rocks are Early Precambrian.
Source: GNU records (USGS DDS-6; Reston GNULEX).


Publication:
Brace, W.F., 1953, The geology of the Rutland area, Vermont: 
   Vermont Geological Survey Bulletin, no. 6, 124 p.
Usage in Publication:
Mendon formation

Modifications: Geologic Province: Dominant Lithology:
 Revised
 New England province
 

Summary:
Lowermost member of Mendon formation is here referred to as Nickwacket member [rank reduced from Nickwacket graywacke of Keith (1932)]. Consists of graywacke, quartzite, and conglomerate. Thickness ranges from 25 to 800 ft. Overlies Mount Holly complex; underlies Forestdale member of Mendon.
Source: GNU records (USGS DDS-6; Reston GNULEX).


Publication:
Zen, E-an, 1967, Time and space relationships of the Taconic 
   allochthon: Geological Society of America Special Paper, 97, 
   107 p.
Usage in Publication:
Mendon Formation*

Modifications: Geologic Province: Dominant Lithology:
 Age modified
 New England province
 

Summary:
Age of Mendon given as Cambrian(?). [No reasons given. No mention of previous ages of other workers.]
Source: GNU records (USGS DDS-6; Reston GNULEX).


Publication:
Ayuso, R.A., and Robinson, G.R., Jr., 1984, Geologic map of the 
   Lye Brook Wilderness, Bennington and Windham Counties, Vermont: 
   U.S. Geological Survey Miscellaneous Field Studies Map, 
   MF-1609-A, 1 sheet, scale 1:48,000
Usage in Publication:
Mendon Formation*

Modifications: Geologic Province: Dominant Lithology:
 Age modified
 New England province
 

Summary:
Age changed to Early Cambrian(?) because Mendon is overlain by formations of Early Cambrian age.
Source: GNU records (USGS DDS-6; Reston GNULEX).


Publication:
Burton, W.C., 1993, Bedrock geologic map of the Sunderland 
   quadrangle, Bennington and Windham Counties, Vermont: U.S. 
   Geological Survey Miscellaneous Field Studies Map, MF-2224, 
   1 sheet, scale 1:24,000
Usage in Publication:
Mendon Formation

Modifications: Geologic Province: Dominant Lithology:
 Not used
 New England province
 

Summary:
Rocks previously mapped as Mendon Formation in this area are here called Dalton Formation following the usage on the Vermont State geologic map by Doll and others (1961).
Source: GNU records (USGS DDS-6; Reston GNULEX).