Hartford's growing skyline looks at its proud reflection in waters of the Connecticut River. The River flows down the Central Valley for most of its passage through southern New England. Much of Connecticut's 20th-century development has been centered on the Connecticut River as it flows through the Central Valley lowlands. Underlying the Central Valley lowlands is a soft, easily eroded rock known as brownstone. A roadcut on Route 40 in Hamden exposes the tilted layers of brownstone bedrock. Over millenia, deep erosion of the brownstone carved out the gentle landscapes we know today as the Central Valley. This view faces north; the brownstone layers tilt down to the east.