PROCEEDINGS 
OF THE 
NINTH ANNUAL SESSION 
OF THE 
IOWA ACADEMY OF SCIENCES. 
The ninth annual meeting of the Iowa Academy of Sciences 
was held in the Y. M. C. A. building at Des Moines, December 
27 and 28. The following papers were read in full or by title, 
and by the action of the Academy were referred to a committee 
of publication consisting of C. R. Keyes, T. P. Hall and H. P. 
Bain: 
J. E. Todd and H. Foster Bain— I nter-Loesial Till near Sioux City. 
H. Foster Bain — Preglacial Elevation of Iowa. Mississippian Rocks of 
Central Iowa. 
Charles R. Keyes — Secular Decay of Granitic Rocks. Synopsis of Amer- 
ican Paleozoic Echinoids. Opinions Concerning the Age of the Sioux 
Quartzite. Illustrations of Glacial Planing in Iowa. 
Arthur J. Jones — Record of the Grinnell Deep Boring. Topaz Crystals 
of Thomas Mountain, Utah. 
A. G. Leonard — L ansing Lead Mines. 
P. M. Fultz — How Old is the Mississippi? Formation of the Flint Beds of 
the Burlington Limestones. Coincidence of Present and Preglacial 
Drainage System in Extreme Southeastern Iowa. Extension of the 
Illinois Lobe of the Great Ice Sheet into Iowa. Glacial Markings in 
Southeastern Iowa. 
S. Calvin — Maquoketa Shales in Delaware Countv, Iowa. 
William H. Norton — Occurrence of Megalomus Canadensis (Hall), in the 
LeClaire Beds at Port Byron, Illinois. Geological Section of Y. M. C. 
A. Artesian Well at Cedar Rapids, Iowa. 
Launcelot ay. Andrews — President’s Address. Recent Advances in the 
Theory of Solutions. 
