What is the longest mountain chain in North America?
North America separated from Eurasia as its own continent during the mid-Cretaceous period. The Rockies and other western mountain ranges began forming around this time from a period of mountain building called the Laramide orogeny, between 80 and 55 million years ago. The formation of the Isthmus of Panama that connected the continent to South America arguably occurred approximately 12 to 15 million years ago, and the Great Lakes (as well as many other northern freshwater lakes and rivers) were carved by receding glaciers about 10,000 years ago. North America is the source of much of what humanity knows about geologic time
Mountain chain Mountain chain A mountain chain is a row of high mountain summits, a linear sequence of interconnected or related mountains, or a contiguous ridge of mountains within a larger mountain range. The term is also used for elongated fold mountains with several parallel chains ("chain mountains"). While in mountain ranges, the term mountain chain is common, in hill ranges a sequence of hills tends to be referred to a ridge or hill chain. Elongated mountain chains occur most frequently in the orogeny of fold mountains, (that are folded by lateral pressure), and nappe belts (where a sheetlike body of rock