Material in the public domain. No restrictions on use.
Creative Commons License
This work has been identified with a Creative Commons Public Domain Mark 1.0.
Beyer, Samuel Walker
"The Sioux Quartzite and Certain Associated Rocks,"
Iowa Geological Survey Annual Report:
Vol. 6: p. 67-112.
Available at: http://ir.uiowa.edu/igsar/vol6/iss1/4