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.
View Slideshow View Thumbnails. The United States became a continental nation with the purchase of Louisiana from France in 1803 and the settlement of the lands beyond the Appalachian Mountains. Westward expansion fueled conflict with Native populations and led to their forced removal.