Digital Data for Detailed Surficial Geology Maps

Boundaries and Polygons

These datasets contain boundaries and polygons of surficial geology units mapped at a scale of 1:24,000. The Maine Geological Survey used this data to produce Detailed Surficial Geology Maps. Surficial deposits such as sand, gravel, clay, and other unconsolidated materials that overlie bedrock are shown. They cover most of Maine's land surface and include sediments deposited by water, wind, and glacial ice. Glacial deposits are by far the most abundant surficial materials in Maine. Attribute tables contain explanations of geologic units, line types, and features.

Available surficial geology shapefiles for each quadrangle include the following:

  • Unit contacts - surficial geologic unit lines
  • Unit polygons - surficial geologic unit polygons
  • Features - moraines, esker ridges, ice margin positions, etc.
  • Points - striations, drumlins, fossil localities, etc.
  • Thin drift - thin drift areas, boulder fields, disturbed earth, etc.

Supporting Data

Surficial geology boundaries were delineated based in part on the surficial materials dataset. The Maine Geological Survey used this data to produce Surficial Materials Maps. This dataset contains point data describing the textures of surficial sediments, independent of interpretations regarding their origin, mapped at a scale of 1;24,000. Thickness of gravel, sand, silt, clay, and diamicton is shown. Data comes from auger holes, test pits, well logs, test borings, and gravel pits. Point data was compiled and digitized by the Maine Geological Survey from data compiled on USGS 7.5' quadrangle bases. The point attribute table contains information on the type of data point and, where appropriate, depth to bedrock, depth to water table, well yield, and/or material type and thickness.

Seismic line data were also used to help delineate surficial geology boundaries. This dataset contains line data describing the results of 1-channel and 12-channel seismic refraction studies mapped at a scale of 1:24,000. The results include the depth to the water and depth to the bedrock.

User Note

The digital data may not include information from the most recently published surficial geology maps. This data will be updated periodically but may be out of step briefly with published maps. The user should check the source attributes associated with the surficial geology data (points/lines/polygons) and verify that the digital data reflects the current published map for the quadrangle. The user can view the most recently published maps or check the source for the cited open-file map in the Bibliography of Maine Geology by searching for the open-file number (e.g. 04-93) in the keyword search source field.


The shapefiles are available by quadrangle in zipped file format. Click on the links below to download.


Last updated on August 8, 2013