A fall line (or fall zone) is a geomorphologic unconformity (e.g., monoclinal faulting or flexing) between an upland region of relatively hard crystalline basement rock and a coastal plain of softer sedimentary rock. A fall line is typically prominent when crossed by a river, for there will often be rapids or waterfalls. Many times a fall line will recede upstream as the river cuts out the uphill dense material, often forming “c”-shaped waterfalls. Because of these features riverboats typically cannot travel any farther inland without portaging, unless locks are built there. On the other hand, the rapid change in elevation of the water, and the resulting energy release, makes the fall line a good location for water mills, grist mills, and sawmills. Because of the need for a river port leading to the ocean, and a ready supply of water power, settlements often develop where rivers cross a fall line.
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Famous quotes containing the words fall and/or line:
“I’ve always wondered why European politicians as a group seemed brighter than American politicians as a group. Maybe it’s because many American politicians have the race issue to fall back on. They become lazy, suspicious of innovative ideas, and as a result American institutions atrophy.”
—Ishmael Reed (b. 1938)
“One line typed twenty years ago
can be blazed on a wall in spraypaint
to glorify art as detachment
or torture of those we
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—Adrienne Rich (b. 1929)