Door County, the peninsula that separates Green Bay from Lake Michigan, was heavily shaped--and reshaped--by glaciers. This bulletin explains how ice sculpted the bedrock surface, creating intriguing sets of paired bays where channels cut across the peninsula. Water levels also fluctuated drastically, leaving behind evidence of significantly higher shorelines. This 44-page book puts what you see today into context against the county's glacial past. The accompanying map (also sold separately) shows the geology draped over the land surface.