As presently defined, the Old West Side is basically a residential neighborhood bounded by South Main Street and the Ann Arbor Railroad tracks on the east, West Huron on the north, Crest, Soule and South Seventh on the west and Pauline on the south. This area includes sections that are not similar in age, building style or type. The topography is characteristic of Ann Arbor in that it is sloped slightly to the northeast with undulations typical of the glacial moraine geology of the area. Most of the older major streets are laid in a grid matching compass lines with two exceptions. West Liberty shows it origins as a trail and runs "southwest/northeast." Newer blocks exhibit curving streets and cul-de-sacs popular at the time of their creation.