SILURIAN

The name given by Murchison to a series of rocks forming the upper subdivision of the sedimentary strata found below the old red sandstone, and formerly de signaled the greywacke series. These strata are well de vcloped in that part of England and Wales formerly included in the ancient British kingdom of the Siiures. See Geology. SILURID ANS, Siluriilte. (Lat. silurus, a sheatk-fish.) The name of the family of tishes of which the genus Silurus is the type, and which includes the electric silurus (Malajrterurus electric us). They are chiefly distinguished by the want of true scales, having merely a naked skin, or large o eous plates. A strong o eous spine forms the first ray of the dorsal and pectoral fins except in the genus Malap terurus. [s. 1140]