1. Map showing the thickness and character of Quaternary sediments in the glaciated United States east of the Rocky Mountains. Northern Great Lake States and central Mississippi Valley states, the Great Lakes, and southern Ontario (80⁰31ʹ to 93⁰ west longitude) Author/Creator: Geological Survey (U.S.) Publication/Creation: Denver, CO : Information Services [distributor]. Resource Type: Map Access & Availability: Loading