Bedrock underlies surficial materials such as sand, gravel, glacial deposits, and soil, and in combination with these earth materials forms the foundation for plant and animal life.
Bedrock includes igneous, sedimentary and metamorphic rock types.
In Vermont, some of the bedrock is exposed at the surface, but most is hidden by surficial cover. Most rocks originate as deposits of sediment along continental margins and in ocean basins, as volcanic extrusions, or as intrusive rocks at depth in the earth's crust. Rocks are usually folded, faulted, transported, metamorphosed, and form mountain belts at active plate boundaries during plate collisions. Rocks exposed at the surface are generally being eroded or destroyed slowly over time by wind, water and ice. All of these processes are evident in rocks of Vermont, and geologists use bedrock maps to understand the rocks and structures that are the record of more than one billion years of geologic time.