The smallest province in the state, it is confined to the northwest corner of the state. The Kittatinny Valley is a part of the Great Appalachian Valley and contain some of the oldest rocks of the province known as the Matinsburg shale created during the Ordovician period. At the edge of this valley is the Kittatinny Ridge which is from 1500 feet to 1800 feet. The ridge goes in a northeast-southwest axis. Beyond this ridge, there are series of rolling hills and small ridges underlain by Silurian and Devonian aged rocks.