Bedrock Geologic Map of the Bellows Falls 7.5- x 15-Minute Quadrangle, Windham and Windsor Counties, Vermont, and Sullivan and Cheshire Counties, New Hampshire

Scientific Investigations Map 3535
Prepared in cooperation with the State of Vermont, Vermont Agency of Natural Resources, Vermont Geological Survey; and the State of New Hampshire, Department of Environmental Services, New Hampshire Geological Survey
By: , and 

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Introduction 

The bedrock geology of the Bellows Falls 7.5- x 15-minute quadrangle, Vermont and New Hampshire, consists of polydeformed Ordovician to Devonian metasedimentary, metavolcanic, and metaplutonic rocks of the Connecticut Valley trough, Bronson Hill anticlinorium (or Bronson Hill terrane), and the Central Maine terrane. Previous work in this area includes a 1:62,500-scale published map and text (1946), State geologic maps of New Hampshire (1997) and Vermont (2011), and various maps and reports presented largely as parts of field trip guidebooks. A provisional open-file map of the geology of the Vermont part of the Bellows Falls 7.5- x 15-minute quadrangle, completed in 1997, is incorporated and revised on this map based on additional fieldwork.

This study recognizes three major structural levels from west to east and from lowest to highest: (1) autochthonous rocks of the Connecticut Valley trough; (2) allochthonous rocks of the New Hampshire sequence and Bronson Hill arc in the Monroe thrust sheet (or nappe), including the Skitchewaug nappe; and (3) allochthonous rocks of the Fall Mountain thrust sheet or nappe.

Suggested Citation

Merschat, A.J., Walsh, G.J., Valley, P.M., McAleer, R.J., and Armstrong, T.R., 2025, Bedrock geologic map of the Bellows Falls 7.5- x 15-minute quadrangle, Windham and Windsor Counties, Vermont, and Sullivan and Cheshire Counties, New Hampshire: U.S. Geological Survey Scientific Investigations Map 3535, 2 sheets, scale 1:24,000, https://doi.org/10.3133/sim3535.

ISSN: 2329-132X (online)

Study Area

Table of Contents

  • Description of Map Units
  • Explanation of Map Symbols
  • Discussion
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Bedrock geologic map of the Bellows Falls 7.5- x 15-minute quadrangle, Windham and Windsor Counties, Vermont, and Sullivan and Cheshire Counties, New Hampshire
Series title Scientific Investigations Map
Series number 3535
DOI 10.3133/sim3535
Publication Date May 21, 2025
Year Published 2025
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Florence Bascom Geoscience Center
Description 2 Sheets: 57.26 x 41.62 inches and 61.56 x 35.74 inches; Data Release
Country United States
State New Hampshire, Vermont
County Cheshire County, Sullivan County, Windham County, Windsor County
Other Geospatial Bellows Falls 7.5- x 15-minute quadrangle
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Additional publication details