Using Geologic Maps

The distribution of materials at and below the land surface affects everyone who lives on this planet. In Maine, earth materials control everything from searching for ground water to siting a house foundation to protecting the environment to mining for precious gems. To make informed decisions, there needs to be a system which portrays the complicated pattern of rocks and earth materials which form the land surface. Geologic maps fill this need, portraying information such as the distribution of rock types and unconsolidated materials such as clay, sand, and gravel; landslide and erosion hazards; ground water availability; and much more. Browse the following pages to find out how to become a more informed reader of geologic maps.

Reading and Understanding Geologic Maps

Use the links in the following table to learn more about the geologic maps produced by the Maine Geological Survey. The columns are as follows:

  • Description - description of the map series, and links to the map explanation and sidebar.
  • How to read - tips on how to read the geologic map.
Bedrock Geology
   Map series Description How to read
   Bedrock Yes Yes

Coastal Marine Geology
   Map series Description How to read
   Bluffs Yes Yes
   Marine Geologic Environments Yes
   Coastal Sand Dune Maps Yes Yes
   Inner Continental Shelf Yes

Economic Geology
   Map series Description How to read
   Peat Resource Evaluation Yes

Geologic Hazards
   Map series Description How to read
   Landslide Hazards Yes Yes
   Landslide Susceptibility Yes

Surficial Geology
   Map series Description How to read
   Surficial - detailed Yes Yes
   Surficial - reconnaissance Yes
   Surficial - 1:250,000 Yes
   Surficial Materials Yes Yes

Water Resources
   Map series Description How to read
   Sand and Gravel Aquifers Yes Yes
   Bedrock Ground-Water Yes
   National Wetlands Inventory Yes

Last updated on October 12, 2011