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National Geologic Map Database
Map showing publication footprint
  • Usage in publication:
    • Cram Hill formation
  • Modifications:
    • Named
  • Dominant lithology:
    • Slate
    • Phyllite
    • Schist
    • Quartzite
  • AAPG geologic province:
    • New England province
Publication:

Currier, L.W., and Jahns, R.H., 1941, Ordovician stratigraphy of central Vermont: Geological Society of America Bulletin, v. 52, no. 9, p. 1487-1512.


Summary:

Named the Cram Hill formation for Cram Hill, Washington Co., VT. Consists of gray to black slate and phyllite grading downward into quartz-chlorite-sericite schist; thin to massive quartzite beds at bottom, siliceous volcanics at top. Greenstone dikes are locally abundant. Thickness is 1500 to 2600 feet. Overlies unnamed Ordovician(?) schists and underlies the Shaw Mountain formation. Unit is equivalent to the upper part of the "Missisquoi" schists of Richardson (1919). The Cram Hill is of Ordovician age.

Source: GNU records (USGS DDS-6; Reston GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Cram Hill Formation*
  • Modifications:
    • Overview
  • AAPG geologic province:
    • New England province
Publication:

Ratcliffe, N.M., and Armstrong, T.R., 1999, Bedrock geologic map of the West Dover and Jacksonville quadrangles, Windham County, Vermont: U.S. Geological Survey Miscellaneous Investigations Series Map, I-2552, 2 sheets, 30 p., scale 1:24,000 [Available online from the USGS PubsWarehouse: http://pubs.er.usgs.gov/pubs/i/i2552]


Summary:

The Cram Hill Formation in Windham Co., VT consists of homogeneous, rusty, tan- to dark-gray weathering, pyritiferous, carbonaceous, ilmentite-chlorite-plagioclase-muscovite-quartz schist with distinctive fissile parting along cleavage surfaces. Locally contains 1 to 10 cm thick plagioclase-quartz-muscovite granofels some of which are graded and contain abundant angular and rounded blue-quartz pebbles. Unit is typically cross-cut by mafic dikes and sills of the North River Igneous Suite. Overlies the Moretown Formation. The Cram Hill is of Ordovician age.

Source: GNU records (USGS DDS-6; Reston GNULEX).


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.

"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).

Slash (/) indicates name does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).