Kansan, and Nebraskan, have been abandoned by North American Quaternary geologists and merged into the Pre-Illinoian. At this time, the Cromerian is correlated with the period of time, which includes the Pre-Illinoian C, Pre-Illinoian D, and Pre-Illinoian E glaciations of North America.

Proposals for structuring the Cromerian complex have become quite confusing. Great potential for a full breakdown has been provided by the extensive, continental series at