Achondroplasia is one of the most common types of dwarfism. Learn about its causes, diagnosis, and treatment. Achondroplasia is one of the most common types of dwarfism.
Westward Expansion (1807-1912) The Surge West. Summary. The westward movement of the American population occurred in intermittent flurries of settlement. The first began early in the nation's history, resulting in the statehood of Vermont, Kentucky, Tennessee, and Ohio, all of which were admitted to the Union between 1791 and 1803.
1 The historical expansion of the United States territory westward. 2  The mural  Westward Movement: Justice of the Plains and Law Versus Mob Rule  by American artist John Steuart Curry at the Department of Justice building in Washington, D.C. 3  Westward Expansion Trails used by American migrants between 1830 and 1870.