USGS - science for a changing world

Mineral Resources On-Line Spatial Data

Mineral Resources > Online Spatial Data > Geology > by state > Massachusetts

Mount Toby Formation

Mount Toby Formation - Breccia of amphibolite at Whitmore Ferry; interpreted as landslide deposit. The Mount Toby Conglomerate is here revised and renamed the Mount Toby Formation of the Newark Supergroup. It includes only the sedimentary strata in the Deerfield basin above the slump zone unconformity defined by Cornet (1977), or its projected equivalent at its contact with the underlying Turners Falls Sandstone. It includes conglomerates at the type locality, landslide deposits within the conglomerate, and sandstone and lake beds above the slump zone unconformity, which were formerly included in the Turners Falls Sandstone. Other rocks mapped as Mount Toby Conglomerate by Emerson (1898) in the Hartford, Deerfield, and Northfield basins have been assigned to the Portland, Sugarloaf, and Turners Falls Formations. Age is Sinemurian and Pliensbachian, based on the discovery by Cornet (1977) of palynoflora in these strata (Robinson and Luttrell, 1985).
StateMassachusetts
NameMount Toby Formation
Geologic ageLower Jurassic
Original map labelJma
CommentsPart of Mesozoic Basins (Jurassic and Triassic Rocks); Sedimentary and Volcanic Rocks of Deerfield and Northfield Basins. Secondary unit description per MA003 as reported in USGS Geologic Names lexicon (ref. MA024): The Mount Toby Conglomerate is here revised and renamed the Mount Toby Formation of the Newark Supergroup. It includes only the sedimentary strata in the Deerfield basin above the slump zone unconformity defined by Cornet (1977), or its projected equivalent at its contact with the underlying Turners Falls Sandstone. It includes conglomerates at the type locality, landslide deposits within the conglomerate, and sandstone and lake beds above the slump zone unconformity, which were formerly included in the Turners Falls Sandstone. Other rocks mapped as Mount Toby Conglomerate by Emerson (1898) in the Hartford, Deerfield, and Northfield basins have been assigned to the Portland, Sugarloaf, and Turners Falls Formations. Age is Sinemurian and Pliensbachian, based on the discovery by Cornet (1977) of palynoflora in these strata (Robinson and Luttrell, 1985).
Primary rock typesedimentary breccia
Secondary rock type
Other rock types
Lithologic constituents
Major
Unconsolidated > Coarse-detrital (Landslide)Breccia of amphibolite at Whitmore Ferry; interpreted as landslide deposit.
Map references
Unpublished Digital Geologic Map of Massachusetts received from Rudi Hon at Boston College in 1998.
Unit references
Zen, E-An (ed.), Goldsmith, R. (comp.), Ratcliffe, N.M. (comp.), Robinson, P. (comp.), Stanley, R.S. (comp.), Hatch, N.L., Jr., Shride, A.F., Weed, E.G.A., Wones, D.R., 1983, Bedrock Geologic Map of Massachusetts: U.S. Geological Survey, Reston, VA, scale 1: 250,000.
Robinson, Peter and Luttrell, G.W., 1985, Revision of some stratigraphic names in central Massachusetts, IN Stratigraphic notes, 1984: U.S. Geological Survey Bulletin, 1605-A, p. A71-A78.
USGS Geologic Names Lexicon (GEOLEX)
Geographic coverageFranklin

Show this information as [XML] - [JSON]

AccessibilityFOIAPrivacyPolicies and Notices

Take Pride in America logoUSA.gov logoU.S. Department of the Interior | U.S. Geological Survey
URL: http://mrdata.usgs.gov/geology/state/sgmc-unit.php?unit=MAJma;0
Page Contact Information: Peter Schweitzer