1.5-1.2 billion years ago: The igneous rocks of the St. Francois Mountains formed (Seeger 2008).
520 million years ago: Tectonic plate movement lowered the Ozark Region below sea level. Sedimentary rocks built up, sea levels dropped, rose again, and the process repeated. (Seeger 2008).
200 million years ago: The supercontinent Pangeasplit up.
100 million years ago:The North Polewas pretty warm, almost tropical. Missouri was underwater.
65 million years ago: An asteroid hit Earth, causing it to start cooling and catalysing a migration of plants from the South Pole to the North Pole.
2.6 million years to 12,000 years ago: The last major glaciation on Earth occurred. The northern area of what is now the US and Canada was covered in ice. Missouri had a boreal-type forest, as pictured below.
General History of Missouri
12,000 years ago: Paleoamerican settlements began forming in Missouri.
1815: Mining of high quality iron started in Shepherd Mountain, part of the St. Francois Mountains (Seeger 2008).
January 8, 1818: The first petition was made for Missouri to become a state.
1820: Missouri was allowed to enter the Union as a slave state under the “Missouri Compromise,” which also brought Maine in as a free state. Missouri’s statehood was a national issue at this time because of slavery. After the compromise, the area north of the 36’30” line from theLouisiana Purchasewas to be free of slavery forever.
1858: The St. Louis and Iron Mountain railroad was completed to ship iron from mines to the Mississippi River and cities nearby. Eventually, this railroad became the Missouri Pacific Railroad (Seeger 2008).