BIBLIOGRAPHY OF THE DRIFTLESS AREA 
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1915 
Howell, J. V., The Occurrence and Origin of the Iron Ores of Iron 
Hill, near Waukon, Iowa: Iowa Geol. Survey, Vol. XXV, pp. 54-62. 
Martin, Lawrence, The Discovery of the Painted Stone, An Early 
Observation of the Driftless Area: Jour. Geography, Vol. 14, No. 2, 
pp. 58-59. 
Shipton, W. D., The Occurrence of Barite in the 1 Lead and Zinc 
District of Iowa, Illinois and Wisconsin: Iowa Acad. Sci., Vol. XXII, 
pp. 237-241. 
Trowbridge, A. C., Physiographic Studies in the Driftless Area: 
Bull. Geol. Soc. America, Vol. 26, No. 1, March, p. 76. 
1916 
Colby, Charles C., The Driftless Area of Minnesota, A Geographic 
Unit: Jour, of Geography, Vol. 14, No. 6, pp. 165-167. 
Hughes, U. B., A Correlation of the Peneplains of the Driftles® 
Area: Iowa Acad. Sci., Voh XXIII, pp. 125-132. 
MacClintock, Paul, The Wisconsin River Valley below Prairie du 
Sac, Unpublished Thesis, University of Chicago. 
Martin, Lawr.ence, The Physical Geography of Wisconsin: Wisconsin 
Geol. and Nat. Hist. Survey, Bull. No. XXXVI. 
Shaw, E. W., and Trowbridge, A. C., U. S. Geol. Survey Geol. Atlas, 
Galena-Elizabeth folio, 
Shipton, W. D., The Geology of the Sparta Quadrangle, Wisconsin, 
Unpublished Thesis, University of Iowa. 
Shipton, W. D., A Note on Fulgurites from Sparta, Wisconsin: Iowa 
Acad. Sci., Vol. XXIII, p. 141. 
Shipton, W. D., A New' Stratigraphic Horizon in the Cambrian 
System of Wisconsin: Iowa Acad. Sci., Vol. XXIII, pp. 142-145. 
Trowbridge, A. C., and Shaw, E. W., Geology and Geography of the 
Galena and Elizabeth Quadrangles, Illinois: Illinois Geol. Survey, 
Bull. No. 26. 
Department of Geology, 
The State University. 
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