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 Historic District Places. The Galena Historic District contains more than 1,000 buildings constructed before 1900 that are considered contributing properties. The center of downtown Galena is laid out in three parallel segmental tiers starting at Main Street closest to the river. Beyond Main Street, and at a higher elevation, are Bench and Prospect Streets. Main Street forms the primary commercial strip through Galena and is lined with buildings two, three, and four stories tall. Most of Main Street's structures are built of red brick and cast in Federal style of the simple commercial style of the 1840s. On Bench Street, most of