Claim: The Ozarks are in North America.

The Appalachian Mountains -LRB- -LSB- æpəˈlæʃᵻn , _ - ˈleɪtʃᵻn -RSB- , There are at least eight possible pronunciations depending on three factors :  Whether the stressed vowel is -LSB- slinkeɪ -RSB- or -LSB- slinkæ -RSB- ,  Whether the `` ch '' is pronounced as a fricative -LSB- slinkʃ -RSB- or an affricate -LSB- slinktʃ -RSB- , and  Whether the final - ia is the monophthong -LSB- slinkᵻ -RSB- or the vowel sequence -LSB- iə -RSB- . les Appalaches -RRB- , often called the Appalachians , are a system of mountains in eastern North America . The Appalachians first formed roughly 480 million years ago during the Ordovician Period . It once reached elevations similar to those of the Alps and the Rocky Mountains before naturally occurring erosion . The Appalachian chain is a barrier to east-west travel , as it forms a series of alternating ridgelines and valleys oriented in opposition to most roads running east or west .   Definitions vary on the precise boundaries of the Appalachians . The United States Geological Survey -LRB- USGS -RRB- defines the Appalachian Highlands physiographic division as consisting of thirteen provinces : the Atlantic Coast Uplands , Eastern Newfoundland Atlantic , Maritime Acadian Highlands , Maritime Plain , Notre Dame and Mégantic Mountains , Western Newfoundland Mountains , Piedmont , Blue Ridge , Valley and Ridge , Saint Lawrence Valley , Appalachian Plateaus , New England province , and the Adirondack provinces . < ref  name = `` USGS-Water '' >  </ref> A common variant definition does not include the Adirondack Mountains , which geologically belong to the Grenville Orogeny and have a different geological history from the rest of the Appalachians . < ref  name = geomorph > </ref> < ref  name = peakbag >  </ref> < ref  name = weidensaul >  </ref>