ACID SULFATE SOILS - Sawgal.umd.edu - University of Maryland

profile and a midden landscape when the soil was tilled from that site appear
on page 67 in the Fanning and Fanning (1989) book.
Picture X1. Carol Gordon, (now, 2011, Carol Loopstra) who is a short
person, holding a tiling spade (sharp shooter) standing on top of Native
American oyster shell kitchen midden exposed on low cliff above tidal
Potomac River just a short distance (50 meters) upriver from where the trail
from the Loyola Retreat House reaches the river thru a creek valley to the
right of where Carol is standing.
This site will also afford an opportunity to view other parts of the cliff face
to see the oxidized vs. un-oxidized parts of the soil-geologic column that are
in marine sediments of Miocene (probably Calvert formation) and/or Eocene
(probably Nanjemoy formation) age. We are hoping to get out to this site
for a further look before we bring the tour group here. One of the interesting
features that occurs in the cliff face are what we think are petrified
(silicified) tree logs that have petrified worm burrows within them – see the
picture, X2, on the following page.
An acid sulfate weathering profile with its lower part in the un-oxidized
Nanjemoy (Eocene) formation was studied on a 6 meter high cliff about a
mile farther up river from the Retreat House cliff on the Mt. Air estate
(Wagner, 1982). There the cliff was in a cut river terrace. At the Retreat
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