OXUCLÆ, in natural history, the name of a genus of fossils of the class of selenite, but of the columnar, not the rhomboidal kind. Of this genus there are only two known species: 1. A fine kind with thin flakes and transverse filaments, found in the clayey banks of the river Nen, near Peterborough in Northamptonshire; and, 2. A dull kind with thick plates and longitudinal filaments. This is not uncommon in Yorkshire, and lies sometimes in a yellow, and sometimes in a blue clay.