The Orangeville Rise is the spring head of Lost River in the town of Orangeville in northwestern Orange County. The site is about 6 mi (9.6 km) northeast of French Lick and 9 mi (14.4 km)southwest of Mitchell. (See location in Fig. 1; also, the inset mapin Fig. 5 shows locations of other features mentioned here.) The Orangeville Rise is owned by the Nature Conservancy and is a National Natural Landmark registered by the U.S. National ParkService. The spring is the most accessible of several sites that arecommonly visited on field trips and are considered to be focalpoints that depict significant aspects of subterranean drainage in the Lost River basin. In addition to the Orangeville Rise, the other nearby sites singled out here are the Rise of Lost River, Tolliver Swallow Hole, and Wesley Chapel Gulf.

The Lost River drainage basin heads on the Mitchell Plain, a low limestone plateau developed on the westward-sloping vale of an east-facing cuesta. The dip of the strata is only slightly greaterthan the general slope of the plain. To the west, the Crawford Upland is a rugged hilly area separated from the Mitchell Plain bythe east-facing Chester Escarpment. Similar physiographic unitsto the south in Kentucky are the Mammoth Cave Plateau and the Pennyroyal Plateau separated by the Dripping Springs Escarpment.A few major streams flow in entrenched sinuous valleyswestward across the Mitchell Plain and the Crawford Upland,

Most of the eastern part of the Mitchell Plain is mantled with clay