Lost River - Karst Information Portal

2007 NSS Convention Guidebook
Pilot Knob is the highest elevation in
Crawford County at about 930 feet and rises about
100 feet above the surrounding plateau, which
then gives way to deeply incised valleys draining
to the Ohio River (Figure 13). The Knob is a
towering erosional remnant and topographical
feature capped by likely the eastern-most outcrop
of by the lower-most Pennsylvanian sandstone,
the Mansfield Sandstone. Pilot Knob is almost
really a “butte” and is visible for miles around.
The top of the Mississippian-age Chester Series
is a major unconformity, and the Pennsylvanianaged
Mansfield rests unconformably on many
different Mississippian-aged units regionally.
According to Malott (pp 242–243, 1950)
the Mansfield at the top of the Knob covers a
width of about 100 yards and has a thickness of
about 25 feet. The Mansfield overlies a shaley
The Crawford Upland, located in southcentral
Indiana, is underlain primarily by
clastic sedimentary rocks with a general west to
east increase in the areal percentage of exposed
carbonates. Associated with spatial trends in
bedrock lithology are changes in landform
morphology and landform assemblages. These
changes have been quantified using principal
components analysis on data measured from
United States Geological Survey 7.5-minute
topographic maps for 105 small (