Ira Formation

Same description as Hortonville Formation - Dark-gray siliceous shale and phyllite containing thin beds of bluish-gray argillaceous limestone and minor beds of gray to tan quartzite. Grades into limy shales of the Stony Point Formation. Unit mapped along east side of the Taconic allochthon south to Bennington. Vermont Valley sequence and Middlebury synclinorium (above the Orwell and Champlain thrusts).
State Vermont
Name Ira Formation
Geologic age Upper Ordovician
Lithologic constituents
Sedimentary > Clastic > Mudstone > ShaleDark-gray siliceous shale and phyllite.
Sedimentary > Carbonate > Limestone (Bed)Thin beds of bluish-gray argillaceous limestone.
Metamorphic > Metasedimentary > Metaclastic > PhylliteDark-gray siliceous shale and phyllite.
Metamorphic > Metasedimentary > Metaclastic > QuartziteMinor beds of gray to tan quartzite.
NGMDB product
Counties Rutland