Description: One of Maine's distinctive glacial legacies is the blanket of marine sediments across southern portions of the state. The last continental ice sheet was so thick and heavy that it depressed the Earth's bedrock crust several hundred feet. Even though global sea level was lower in glacial times, this depression enabled the sea to flood low areas of southern Maine as the glacier receded. The marine limit line shows the inland limit of marine submergence. Numerous islands existed in the flooded area but are not shown. The recession of the ice sheet caused the land to rise above the ocean, and a wide variety of sedimentary deposits were released from the melting glacier.
Description: This dataset contains statewide surficial geology map units for Maine at 1:500,000 to 1:250,000 scale. The Maine Geological Survey (MGS) developed the dataset which maps surficial geology map units from their Regional Surficial Geology maps published in 1987. The data for this coverage were digitized and coded from 1:250,000 scale mylars by the J.W. Sewall Co., in 1990, for the Maine Low-Level Radioactive Waste Authority. Some coding and edgematching errors exist. For a detailed description of the surficial unit types see "Surficial Geologic Map of Maine, 1985" available at MGS. The data were updated in 2006 to fix some coastal errors.