About
the Scientists Cliffs Site:
Located
on the western side of the Chesapeake Bay, the
"Calvert Cliffs" were formed over
15 million years ago when all of Southern Maryland
was covered by a warm, shallow sea.
The
cliffs dominate the shoreline of the Chesapeake
Bay extending for more than thirty miles; from
Fairhaven (Anne Arundel County, MD) to near
Drum Point (Calvert County, MD).
Know
Before You Go
Maryland
State Fossil, Ecphora garderae garderae
Wilson, an extinct gastropod (snail).
This fossil snail was one of the first
fossils from the New World to be illustrated
and published in the scientific literature,
dating to about 1770. It was officially
named Maryland's state fossil 1 October
1994.
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They
are considered the best marine Miocene (Miocene
Epoch, 25 million to 6.5 million years ago)
deposit in the world.
Three
formations are recognized in the cliffs; from
oldest to youngest, the Calvert, Choptank, and
St. Marys Formations. These have been further
subdivided into Members and Beds.
Because
of the gentle dip (about 11 feet per mile) of
the deposits to the southeast, different Beds
are exposed at different localities, containing
different sediment types and fossils.
The cliffs and beaches have been collected and
studied from Colonial times to the present.
Over
600 species of fossils have been identified
from these cliffs including the "Maryland
State Fossil" Ecphora gardnerae
gardnerae Wilson.
The most visible fossils are mollusk shells,
with some beds so densely packed that they are
described as "shell beds."
The
most popular fossils are the sharks' teeth.
Other
fossils include microscopic plants and animals,
macroscopic plants, corals, barnacles, crabs,
sand dollars, sea urchins, bony fish, rays,
crocodiles, turtles, birds, terrestrial mammals,
and marine mammals. Many fossils have Calvert
Cliffs as their type locality and some have
been found nowhere else.
The
Calvert Cliffs region is also home to two Federally
threatened species of tiger beetle; Cicindela
dorsalis dorsalis (Northeastern Beach Tiger
Beetle) and Cicindela puritana (Puritan
Tiger Beetle) which live on the broad, sandy
beaches at approximately ten locations in Virginia
and Maryland including four populations in Calvert
County.
Most popular finds include shark
teeth and ray teeth. Here in the left photo,
a complete Spotted Eagle Ray tooth, Aetobatus
sp. (far left) and Requien Shark tooth,
Carcharhinus sp. (upper center). Lower
right is an example of ray teeth. The most ray
teeth found are form are from the spotted eagle
ray, Aetobatus sp. In
the photo on the right you see a variety of
common finds, including a Mako Shark tooth,
Isurus hastalis, (lower right).
Terry
Chesser