Illinoian

 
Pronunciation: /ˌɪlɪˈnɔɪ(j)ən/

adjective

Geology
  • relating to or denoting a Pleistocene glaciation in North America, preceding the Wisconsin and approximating to the Saale of northern Europe.
  • (as noun the Illinoian) the Illinoian glaciation or the system of deposits laid down during it.

Origin:

mid 19th century: from Illinois + -an