Varicolored claystone unit exposed just north of the westbound I-70
overpass. The dashed line is the contact between the claystone and
the overlying Lake Neosho Shale. The base of the Worland Limestone
shows at the top of the photo. The majority of the claystone here is
gray with yellowish orange root structures that vary from distinct
vertical traces to irregular mottles. Rooting shows that this unit is
a paleosol. The arrow points to a light gray layer of sticky clay that
seems to have been a barrier to root penetration by the smaller plants,
since the small root casts change from dominantly vertical to
subhorizontal just above the clay layer. Only larger roots (large dark
yellowish orange mottles below the clay layer) were able to punch
through the clay. Near the bottom of the exposure the claystone is
maroon, with abundant small yellowish orange root casts. The upper
part of the claystone (bracketed interval) was uniformly reduced to
shades of gray during a subsequent marine transgression.
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