Search and compare thousands of words and phrases in British Sign Language (BSL). The largest collection online.
How to sign: a unit of geological time during which a system of rocks formed
"ganoid fishes swarmed during the earlier geological periods";
Similiar / Same: period
Categories: geological time, geologic time
Within this category: Cambrian, Carboniferous, Cretaceous, Devonian, ice age, Jurassic, Mississippian, Ordovician, Pennsylvanian, Permian, Quaternary, Silurian, Tertiary, Triassic