Ore genesis and loses its metal carrying capacity. Ore deposits rarely fit neatly into the categories in which geologists wish to place them. Many may be formed by one or more of the basic genesis processes above, creating ambiguous classifications and much argument and conjecture. Often ore deposits are classified after examples of their type, for instance Broken Hill type lead-zinc-silver deposits or Carlin–type gold deposits. Classification of hydrothermal ore deposits is also achieved by classifying according to the temperature of formation, which roughly also correlates with particular mineralising fluids, mineral associations and structural styles. This scheme, proposed by Waldemar Lindgren (1933)
Galena, Illinois top-ten "Charming Small Towns". Galena is located at (42.418171, −90.431472) along the Galena River, which is one of many tributaries of the Mississippi River. According to the 2010 census, Galena has a total area of , of which (or 99.83%) is land and (or 0.17%) is water. Galena is located in the Driftless Zone, an area that was not covered by glaciers during the recent ice ages. This area, which includes the far northwestern corner of Illinois, escaped glaciation, while almost the entire state was glaciated, nearly to its southern tip. Because it escaped glaciation, this area is known for