Gap (landform)

A gap is a low point or opening between hills or mountains, or in a ridge or mountain range. It may also be called a col, notch, pass, saddle, water gap or wind gap. Most gaps are carved by water erosion from a freshet, stream or river. Gaps cut by freshets are often dry for much of the year and depend on snowpack meltwater, while gaps fed by small springs usually carry a small stream except in the driest seasons. Water gaps frequently cut right through a barrier range, and riverine gaps can form canyons, such as those of the Danube, the Lehigh River Gorge, the Grand Canyon of the Colorado River and the Genesee River, whose cuttings expose strata that record the local geology.