many sinkholes and sinkhole ponds." This portion lacks any true urban center. East Dubuque is really a part of metropolitan Dubuque, while Galena retains the character of a small Midwestern county seat. The valley of the Apple River has a major canyon, with Apple River Canyon occupying much of it. The mouth of this river, near Hanover adjacent to the former Savanna Army Depot, comes close to the southern end of the Driftless Area on the eastern side of the Mississippi (see Lock and Dam No. 13). As in Wisconsin, the Illinois portion of the driftless area was a major early center for Lead and Zinc mining. The city of Galena, Illinois was named after the lead sulfide mineral Galena. References External links "Decoding the Driftless" movie, 2018, created by Sustainable Driftless, Inc., dedicated to inspiring resource conservation and sustainable growth in the Driftless Region. A Sand County Almanac: A book written by Aldo Leopold about the flora and fauna in the Coulee region. The Driftless Area: A Landscape of Opportunities "Driftless Area National Wildlife Refuge", Retrieved July 23, 2007 US Geological Survey description Retrieved July 7, 2007 National atlas description and map Retrieved July 7, 2007 Driftless Area Initiative Retrieved July 2, 2014 Wisconsin Geological and Natural History Survey map showing extent of last glaciation Driftless Region Food and Farm Project Driftless Area Magazine Regions of Wisconsin Pleistocene Geology of Wisconsin Geology of Illinois Geology of Iowa Geology of Minnesota Regions of Illinois Regions of Iowa Regions of Minnesota