basaltic

[Eng. basalt, suffix -ic; Fr. basalt i que.] Composed in greater or smaller measure of basalt; columnar, like basalt, or in any other way pertaining to basalt. "... which indicates with singular precision the age of some, at least, of the basaltic sheets. Duke of Argyll: Q. Jour. Geol. Soc., vii. (1851), pt. i., p. 100.