GEOLOGY AND SOILS OF THE KNOBSTONE ESCARPMENT GEOLOGIC ROUTE MAP - KNOBSTONE TRAIL TRIP The Knobstone Escarpment is the most prominent physiographic feature in Indiana. More than 400 feet high in its southern part, it is only a little less impressive

MONTGOMERY BOONE HENRY WAYNE northward. North of Bloomington it is actually two escarpments. The western one, HANCOCK visible on the surface, extends only a few miles; its northern part is buried by glacial HENDRICKS PARKE PUTNAM Indianapolis drift. The eastern escarpment, though buried throughout its length by a few to a few RUSH hundred feet of glacial deposits, can be traced northwestward for more than a hundred UNION River FAYETTE SHELBY miles. JOHNSON Brook- CLAY Southern limit of ville Cataract Lake Lake MORGAN Wisconsin glacial deposits FRANKLIN The Knobstone Escarpment marks the eastern boundary of the Norman Upland, a OWEN DECATUR physiographic division characterized by hills with steep slopes and thin soils over

MONROE BARTHOL- siltstone bedrock. This division varies greatly in width; in our progress southward we BROWN RIPLEY OMEW

Bloomington O H I O will cross it in its entirety three times. To the west is the Mitchell Plateau, a limestone 46 DEARBORN GREENE plateau replete with sinkholes, underground drainage, and thick terra rossa soils. To Monroe River Lake JENNINGS the east, the Scottsburg Lowland is formed in soft shale bedrock and extensive and 446 OHIO LAWRENCE Knobstone varied glacial deposits. Much of our return route is along this lowland. White Escarpment SWITZERLAND DAVIESS MARTIN 50 JACKSON JEFFERSON White The Knobstone Escarpment and the Norman Upland are underlain by rocks of the Fork 31 135 SCOTT RIVER Borden Group, which is Mississippian in age and which represents a tongue of a great ORANGE Salem Southern limit of westward-prograding delta. The Borden Group is about 500 feet thick and consists older glacial deposits CLARK East 60 mainly of siltstone that ranges in character from soft and shalelike to ledge-forming PIKE DUBOIS Patoka WASHINGTON and sandstonelike. None of the ledges are extensive, however, and no "rim-rock" as Lake CRAWFORD FLOYD such caps the escarpment.

HARRISON PERRY Louisville SPENCER Most upland soils in this region are developed in a "loess cap" a meter or more in original thickness, but on steep slopes the loess is much thinner, probably because of WARRICK OHIO erosion. Principal soils on steep slopes are Weikert and Berks; Gilpin and Zanesville

10 0 30 Miles are found on more gentle slopes and Crider (a limestone-derived soil) caps the 10 0 50 Kilometers escarpment in the southern part of the area. Henry H. Gray K E N T U C K Y Glossary Harrodsburg and Salem Limestones TYPICAL PROFILE OF escarpment: A long, more or less continuous cliff or relatively steep slope facing in one KNOBSTONE ESCARPMENT general direction, breaking the ocntinuity of the land by separating two level or gently (not to scale) sloping surfaces, and produced by erosion or by faulting. loess: A widespread, homogenous, commonly nonstratified, porous, fine-grained deposit Borden Group glacial deposits (mainly siltstone) consisting of predominantly silt and fine sand. prograding: The building foreward or outward toward the sea of a shoreline or coastline. New Albany Shale Devonian limestones terra rossa: A reddish-brown soil found as a mantle over limestone bedrock, typically in karst areas. from Glossary of Geology, Third Edition Indiana Geological and Water Survey https://igws.indiana.edu