Soil
Bedrock on Isle Royale is basalt or sandstone and conglomerates on the 1100 million year old Midcontinent Rift. Most of the island is covered with a thin layer of glacial material. A number of small native copper mines were active in the 1800s but mining was never really prosperous. Recent analyses by the USGS of both unmineralized basalt and copper-mineralized rock show that a small amount of naturally-occurring mercury is associated with mineralization.
Read more about this topic: Isle Royale National Park
Famous quotes containing the word soil:
“As I drew a still fresher soil about the rows with my hoe, I disturbed the ashes of unchronicled nations who in primeval years lived under these heavens, and their small implements of war and hunting were brought to the light of this modern day.”
—Henry David Thoreau (1817–1862)
“The Indian attitude toward the land was expressed by a Crow named Curly: “The soil you see is not ordinary soil—it is the dust of the blood, the flesh, and the bones of our ancestors. You will have to dig down to find Nature’s earth, for the upper portion is Crow, my blood and my dead. I do not want to give it up.””
—For the State of Montana, U.S. public relief program. Montana: A State Guide Book (The WPA Guide to Montana)