Browse Map

Explore away

Explore Map Collection

Check out our basemaps

Print a Map Plus

Generate a high-quality PDF

Field Guide

Discover local flora, fauna, geology, and more

Local Flora & Fauna

Learn the ecology of your area

Local Geology

Learn the geologic formation at your feet

Get Started or Sign In

Welcome

Continue with Apple

Already have an account? Sign In

MAP

Topo

Measure

Topo

Ecoregions

Public Lands

...

BASEMAPS

Default Weather

Temperature

Smoke

...

WEATHER

Clough Quartzite (MASc;0)

Geologic Formation in MA, NH

Print Map

Generate High-Quality PDF

Lithology

Conglomerate

Quartzite

Geologic Age

Llandovery – Wenlock (445.3 Ma – 427.9 Ma ago)

Geologic Unit Label

Quartz-pebble conglomerate, quartzite, and minor mica schist and calc-silicate rocks. Fossils at Bernardston are similar to those at Croyden Mountain, New Hampshire which indicate late Llandoverian age. Parts of the Littleton and Partridge Formations, and Clough Quartzite in MA are here reassigned to the Rangeley Formation [here geographically extended to MA]. The four mapped areas of Clough Quartzite in the Amherst area west of the Connecticut Valley border fault are now interpreted as conglomerate lenses in the Rangeley. Clough is considered the key stratigraphic unit in Bronson Hill anticlinorium because 1) it is dominated by distinctive, readily recognizable rock types, 2) where present, it is base of Silurian-Devonian sequence, resting with detectable unconformity on older rocks, and 3) it contains late Llandoverian fossils at several localities in western NH and adjacent VT, and at Bernardston, MA. Consists mostly of quartz-pebble conglomerate in which pebbles are typically deformed; other lithologies are quartz grit or white to pink, well-bedded quartzite. Locally contains some mica schist beds. On the MA State bedrock geologic map (Zen and others, 1983), thickness is locally exaggerated because at many localities, the unit was only a few meters or less thick and could not be shown at a scale of 1:250,000. Maximum thickness is 200 m on west limb of Northfield syncline. Unconformably overlies Fourmile Gneiss in Pelham dome and in Kempfield anticline, or Ammonoosuc Volcanics over most gneiss domes. Partridge Formation occurs along Clough-Ammonoosuc contact as lenses in many areas (Hatch and others, 1988).

— USGS

Taxonomy

Classified As

Geologic Formation