neo volcanic (ne"ovolkanik)

A term used by Rosenbusch to designate the modern volcanic rocks, or those more recent than the Cretaceous, while those older than this are called by him paleovolcanic. The older eruptive rocks have as a rule undergone a larger amount of alteration (see metamorphism) than the more recent, but this affords no reliable criterion for a general cla ification. Neozoic (nē-ō-zō'ik), a. [ =