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:
“Green, green is El Aghir. It has a railway station,
And the wealth of its soil has borne many another fruit:
A mairie, a school and an elegant Salle de Fetes.
Such blessings, as I remarked, in effect, to the waiter,
Are added unto them that have plenty of water.”
—Norman Cameron (b. 1905)
“A grimy fly can soil the entire wall and a small, dirty little act can ruin the entire proceedings.”
—Anton Pavlovich Chekhov (1860–1904)