huronian

from The Century Dictionary.

• Of or pertaining to Lake Huron, the central one of the chain of great lakes between the United States and British America.

from the GNU version of the Collaborative International Dictionary of English.

• adjective (Geol.) Of or pertaining to certain non-fossiliferous rocks on the borders of Lake Huron, which are supposed to correspond in time to the latter part of the Archæan age.