Who was an American writer responsible for a dissertation concerning  the towns and districts built near sediment formations around Lake Superior?
Iron Range Iron Range refers collectively or individually to a number of elongated iron-ore mining districts around Lake Superior in the United States and Canada. Despite the word "range," the iron ranges are not mountain chains, but outcrops of Precambrian sedimentary formations containing high percentages of iron. These cherty iron ore deposits are Precambrian in age for the Vermilion Range, while middle Precambrian in age for the Mesabi and Cuyuna Ranges, all in Minnesota. Similarly, the Gogebic Range in Wisconsin and the Marquette Iron Range and Menominee Range in Michigan. Natural ores and concentrates were produced from 1848 until the mid 1950s, when taconites and jaspers were concentrated and pelletized started to become the major source of iron production.
American Bottom The American Bottom is the flood plain of the Mississippi River in the Metro-East region of Southern Illinois, extending from Alton, Illinois, south to the Kaskaskia River. It is also sometimes called "American Bottoms". The area is about 175 sqmi , mostly protected from flooding in the 21st century by a levee and drainage canal system. Immediately across the river from St. Louis, Missouri are industrial and urban areas, but many swamps and the major Horseshoe Lake are reminders of the Bottoms' riparian nature. This plain served as the center for the pre-Columbian Cahokia Mounds civilization, and later the French settlement of Illinois Country. Deforestation of the river banks in the 19th century to fuel steamboats had dramatic environmental effects in this region. The Mississippi River between St. Louis and the confluence with the Ohio River became wider and more shallow, as unstable banks collapsed into the water. This resulted in more severe flooding and lateral changes of the major channel, causing the destruction of several French colonial towns, such Kaskaskia, Cahokia, and St. Philippe, Illinois.