The Quaternary Geologic Map of the Lake Erie 4� x 6� Quadranglewas mapped as part of the Quaternary Geologic Atlas of the United States.The atlas was begun as an effort to depict the areal distribution ofsurficial geologic deposits and other materials that accumulated orformed during the past 2+ million years, the period that includes allactivities of the human species. These materials are at the surface ofthe earth. They make up the "ground" on which we walk, the "dirt" inwhich we dig foundations, and the "soil" in which we grow crops. Mostof our human activity is related in one way or another to these surfacematerials that are referred to collectively by many geologists asregolith, the mantle of fragmental and generally unconsolidated materialthat overlies the bedrock foundation of the continent. The maps werecompiled at 1:1,000,000 scale.
