Drybrook sandstone (Chepstow Grit of Stanley Smith) Carboniferous Limestone Series.
Locality details
Caerwent Quarries, 1300 Yds. SE. of Caerwent Church and 1200 Yds. NE. of Dewstone Cophill Quarry, 300 Yds. N. of Cophill Farm and 1700 Yds. ESE. of Itton Court.