Neptunian

Part of speech: adjective (a.)

1. Of or pertaining to the ocean or sea.

2. Formed by water or aqueous solution; as, Neptunian rocks. Neptunian races (Ethnol.), the Malay and Polynesian races. -- Neptunian theory (Geol.), the theory of Werner, which referred the formation of all rocks and strata to the agency of water; -- opposed to the Plutonic theory.