OELRICHS, S.D. — Call it the Grotto of Black Hills Geology. The
historical rock grotto that sits beside a closed Catholic church
in Oelrichs is actually a shrine to St. Therese of the Little
Flower, but the structure is also an impressive monument to the
geological history of southwestern South Dakota. More than 15
different types of collectible minerals, gemstones, fossils and
petrified wood are stacked and grouted into a structure that
stands about 12 feet high, 16 feet long and 6 feet deep. The
rocks that comprise it come from the prairie agate fields and
Badlands fossil beds to the east and the Black Hills caves and
mineral deposits to the west. It contains specimens of
stalagtites and stalagmites, rose quartz, prairie agates,
crystal geodes, schitz, mica, selenite clusters, sandstone
clusters, petrified moss, fossilized coral and much more. Rock
hound Ellen Tilley, who also serves as president of the Western
South Dakota Gem and Mineral Society, has never seen the
Oelrichs grotto, but, like any rock houn