The town is located in a narrow ravine along French Creek. The Falls of French Creek have formed where French Creek cuts across a series of
diabase (
trap rock)
dikes. Erosion of the diabase dikes by the creek has caused huge boulders to fall into the stream, almost filling the creek bed at points. The igneous intrusion that produced these diabase dikes also replaced
limestone or
marble in the surrounding rock with
iron ores. ==History==