The rapids of the James River through the City of Richmond are created by the river crossing the Fall Line. The Fall Line is where the sediments of the Coastal Plain meet the crystalline rocks of the Piedmont. Broken out sections of dam built over the centuries also help to create many of the rapids in Richmond most notably 1st and 2nd break Richmond is the western limit of navigation on the James River. Even today the Port of Richmond serves ocean going vessels. The James River is an estuary of the Chesapeake Bay east of the Fall Line.