A geologic map. Click on image
for a larger view.
Geologic maps show what kinds of rocks and geologic features exist at each location on the map, and the basic relationships between them.
You can determine the rock or sediment type that one would find at a certain place from a geologic map.As examples, take a look at the geologic maps found on page 4, page 7 and page 10 of Rocks, Rails and Trails.