Siegel, Donald I. <br/><br/>
Geochemistry of the Cambrian-Ordovician aquifer system in the northern Midwest, United States / 
by D. I. Siegel 
 - Washington :  United States Government Printing Office,  1989 
 - vii, D1-D76 p. :  ill. (some col.) ;  29 cm. 
 - U.S. Geological Survey professional paper ;  1405-D .
 - Regional aquifer-system analysis--northern Midwest aquifer system .
<br/><br/>Bibliography: p. D56-D60 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Water--Composition--Middle West<br/>Geochemistry--Middle West<br/>Aquifers--Middle West<br/>Geology, Stratigraphic--Cambrian<br/>Geology, Stratigraphic--Ordovician<br/>Geology--Middle West.
<br/><br/><label>Dewey Class. No.: </label>553.790977