Front Matter
Articles
Letter of Transmittal p. 7-8
George F. Kay
Mineral Production in Iowa in 1923 and 1924 p. 9-52
James H. Lees
The Geology of the More Refractory Clays and Shales of Iowa p. 53-90
S. L. Galpin
The Fertilizer Materials of Iowa p. 91-152
John E. Smith
The Distribution of Ash and Sulfur in Iowa Coals as Affected by Washing and Flotation p. 153-166
H. L. Olin and J. R. Troeltzsch
Trilobites of Iowa and some Related Paleozoic Forms p. 167-390
Otto Theodore Walter