Galena, Illinois for mayor and aldermen on May 24, 1841, replacing the board of trustees; Charles S. Hempstead was elected the first mayor with 185 of the 356 votes cast. The first census was also held that year, finding 1,900 inhabitants. By 1845 Galena was producing nearly 27,000 tons of lead ore and Jo Daviess County was producing 80 percent of the lead in the United States. Once one of the most important cities in the state, Galena was a hub on the Mississippi River between St. Louis and St. Paul. Due to erosion, the Galena River is now inaccessible to steamboats.
Broken Hill ore deposit hornblende schists. The ore consists of massive, recrystallised sphalerite-rich, galena-sphalerite and galena-rich sulfide lenses in folded horizons, known as No. 2 Lens Formation and No.3 Lens Formation. Both have distinctive metal ratios and gangue minerals. The ore boundaries are parallel to the bedding planes. According to Gustafson, "There is evidence that the ore has been introduced into an old, already folded, rock and has replaced certain favourable layers of that rock, particle by particle, with large tonnages of garnet, rhodonite, fluorite, marmatite (and wurtzite), galena, and other minerals that constitute the orebodies." The Potosi-Footwall Gneiss is found on both sides