TY  - BOOK
AU  - Heyl,Allen Van
TI  - The geology of the upper Mississippi Valley zinc-lead distict,
AV  - QE75 .P9 no. 309
U1  - 557.7 
PY  - 1959///
CY  - Washington
PB  - U.S. Govt. Print. Off.
KW  - Geology
KW  - Mississippi River Valley
KW  - Zinc mines and mining
N1  - Bibliography: p. 296-303
ER  -