Two nature preserves in the eastern section of The St. Francois Mountains are notable for their exposures of Lamotte sandstone. Deposited during the Cambrian Period, about 500 million years ago, it is among the oldest sedimentary rocks in Missouri.
At the Pickle Springs Natural Area, east of Farmington, visitors walk on, along and through exposures of Lamotte sandstone (see photo) on a two-mile loop trail.
Farther east, Hawn State Park also lies atop this sandstone and the sandy soil that it generates appeals to native shortleaf pines. Indeed, this Park is one of the few in Missouri to actively protect stands of these stately trees (see photo), including through the use of controlled burns.
