1. Map showing the thickness and character of Quaternary sediments in the glaciated United States east of the Rocky Mountains--northern plains states (west of 102⁰ west longitude) Yale Public content 1994. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). The Survey ; For sale by Map Distribution. English. Public. North Dakota and Montana.