Heyl, Allen Van,  1918- <br/><br/>
The geology of the upper Mississippi Valley zinc-lead distict, 
by Allen V. Heyl, Jr. [and others]  With special sections by Arthur E. Flint. Prepared in cooperation with the Wisconsin Geological and Natural History Survey, the Iowa Geological Survey, and the Illinois State Geological Survey. 
 - Washington,  U.S. Govt. Print. Off.,  1959. 
 - x, 310 p.  illus., maps (24 fold. 22 col., in portfolio) diagrs., profiles, tables.  29 cm. 
<br/><br/>Bibliography: p. 296-303. 
<br/><br/><label>LCCN: </label>gs 59000160  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Geology--Mississippi River Valley.<br/>Zinc mines and mining--Mississippi River Valley.
<br/><br/><label>LC Class. No.: </label>QE75  / .P9 no. 309 
<br/><br/><label>Dewey Class. No.: </label>557.7 
<br/><br/><label>Gov. Doc. Class. No.: </label>I 19.16:309/