A maze of rocks, rapids, channels, and islands stretches along the James River between the 14th Street Bridge and the Edward Wiley Memorial Bridge at the Fall Line, where the river drops steeply through a band of hard granite formed by the collision of Africa and North America 300 million years ago. This 1000-mile band of rock from New Jersey to Georgia blocked commercial navigation, but the falling water powered the flour mills, saw mills, and iron foundries that helped make Richmond the economic center of the South. Canals let cargo boats bypass the rapids and also supplied water to turn wheels and turbines, while quarries, canals, granite buildings, and cobblestone walls grew directly from the city's location at the falls of the James.
