The Commissioners' Plan of 1811 stopped at 155th Streetexcept for 10th Avenue which was extended to the northern tip of the island but as the city grew, and subsumed what had been independent villages such as Greenwich Village and Manhattanville, it became clear that a plan of action would be needed for the part of Manhattan above that line. The Common Council directed the city's street commissioner to develop a plan for Upper Manhattan in 1851, but no money was allocated for the task, so there was no result. In any case, any street plan for that area would have had a difficult time in extending the simple rectilinear grid created by the Commissioners for the area below 155th Street, because the topography of Upper Manhattan was significantly more difficult to tame, consisting as it does of extremely steep hills, high ridges made of hard Manhattan schist, and deep valleys caused by tectonic fault lines at what is now Dyckman Street, which transects the Fort Washington Ridge; 155th Street; and at 125th Street, which crosses the Manhattan Ridge to create the Manhattanville Valley.