Where can sand and gravel be found?
Much of the sand and gravel used for construction purposes in Maine was deposited by glacial meltwater. Water runs downhill (unless under pressure in subglacial tunnels!), so most gravel deposits are found in valleys and other lowlands where they were laid down in glacial outwash streams, glacial lakes, or the ocean. Ice-tunnel deposits (eskers) are notable exceptions. Some of these ridges of sand and gravel climb up hillsides and pass through elevated gaps in the hills. Surficial geologic maps are a useful guide to where geologists have found sand and gravel resources.
