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IOWA ACADEMY OF SCIENCES. 
LANSING LEAD MINES. 
BY A. G. LEONARD. 
' [Published by permission of the State Geologist.] 
The mine herein described is located in Allamakee county, 
about five miles northwest of Lansing (Tp. 99 N., R. IV. W., 
Sec. 10, Nw. qr.). It is owned and operated by the Lansing 
Mining and Smelting Company, of which Hon. J. H. Trewin is 
president. 
The mine is of special interest on account of being located in 
the Oneota limestone. As is well known, the lead and zinc 
deposits of this state are confined almost wholly to the Galena 
formation, and moreover, the large ore bodies have occurred in 
the upper part of this limestone. Thus the Dubuque mines are, 
with few exceptions, within 100 feet of the overlying Maquo- 
keta shale, many of the shafts passing through from ten to 
twenty feet of these beds. At Guttenberg, where at one time 
considerable lead was found, the productive openings are at the 
base of the Galena, at its juncture with the Trenton. 
Previous to the discovery of the Lansing mine lead in paying 
quantity had not been found in Iowa below this horizon, and it 
was considered well nigh useless to look for ore in other forma- 
tions. This mine is, so far as known, the only instance in the 
entire Upper Mississippi region where an extensive lead 
deposit occurs in the Oneota limestone, or anywhere below 
the Trenton. 
Another remarkable fact in connection with this deposit is its 
occurrance as a vertical sheet in a north and south fissure. While 
these north and south crevices are not uncommon in the state, 
they are usually of limited extent, and do not contain large 
bodies of ore. But here the sheet is an extensive one, and does 
not as yet show any signs of giving out. 
The deposits, as a rule, are confined to east and west crev- 
ices, where they occur in expansions or openings of the fissures. 
