|THE PITTSFORD MEMBER OF THE LOWER VERNON FORMATION REVISITED: THE TASTINGS SITE (NEW)
PITTSFORD, NEW YORK Samuel J. Ciurca, Jr., Rochester, New York
(ABSTRACT from ABSTRACTS for Rochester Academy of Science, Fall 2006 Scientific Papers Day, hosted by St.
John Fisher College, November 4, 2006)
During July 2006, Wegmans began excavation near their Tastings Restaurant (Monroe Avenue, Pittsford, New York)
for their expansion of their parking lot and encountered, again, parts of the lower Vernon Formation (Salina Group)
including the eurypterid-bearing Pittsford Member (black shale, mudstone and dolostone). This is a continuation of
studies reported previously in the Rochester Academy of Science Abstracts and elsewhere.
Most of the lithologies recognized at the Spring House Commons Site (SHCS) were observed in the material examined
from the Tastings Site. These include the red shale/mudstone and waterlimes that overlie the Pittsford Member and
the Blue Stone that underlies the unit. Within the Pittsford Member, all units were recognized including the very
resistant intercalated waterlimes, the Chunky Bed and particularly the Slate Bed.
Abundant fossil remains were retrieved from most of the units previously observed at the SHCS. Several species were
recovered and continue to emphasize the importance of this unit as a unique repository, locally, of the remains of
prehistoric arthropods that dominated the region over 400 million years ago. A large research collection of fossils
from previous excavations is now part of the eurypterid collection at the Yale Peabody Museum of Natural History in
New Haven, Connecticut.
The Tastings Site provides the first example of a nearly complete pterygotid - a type of eurypterid known to reach
upwards of 10 feet in length. The two 'common' eurypterids within the lower Vernon Formation (Hughmilleria socialis
and Eurypterus pittsfordensis) are represented by numerous isolated specimens of carapaces, tergites, coxae,
telsons and other parts. Many examples of nearly entire individuals of H. socialis were collected.
The bizarre Mixopterus is rare in the fauna and only a partial carapace, a curved telson and spiny leg were observed.
This genus is best known from the rocks of Norway.
Even though most of the Pittsford Member consists of fine-grained sediments, there is much evidence of a
high-energy regime. Scouring is much in evidence, lenticular waterlimes are present, and the thin units indicate swift
changes in sedimentation during what must have been a relatively short period of time. The Pittsford Member starts
with a thin waterlime (Clam Bed) that may be a channel into lower deposits and is succeeded by a hypersaline black
shale (Slate Bed) with eurypterids.
Samples of various structures and lithologies were recovered and will be examined at a later date along with other
fossil remains encountered: clams, ostracods, Lingula sp. and small horseshoe crabs.
ABOVE: Rochester Academy of Science Poster Session, November 4, 2006, showing a fellow looking at a large cast
of Mixopterus kiaeri from the Silurian rocks of Norway. The poster shows photos of three specimens (pertaining to
Mixopterus) that were recovered from the Tastings Site (anterior portion of the animal, a curved telson and a
specimen showing long spines. Photos at the extreme left show excavation techniques. In the center are photos of
Eurypterus pittsfordensis and Hughmilleria socialis.
LEFT: Another view of
the Poster Session at
St. John Fisher College.
There were interesting
displays covering many
disciplines. My favorite
was one exhibiting a
study of fiddler crabs
and their antics. See the
Rochester Academy of
Science website at:
RIGHT: Photo of person
taking a photo of the large
cast of the Mixopterus from
Norway. The cast is at the
bottom of the display.
|Portion of Hughmilleria socialis with
well-preserved operculum at lower
right and closer view in frame to the
left. Integument is often coated with
various crystallized material formed
from groundwater seeping through
bedding planes. Groundwater also
dislocates some integument and
floats to nearby areas.
ABOVE: 112506-1 Hughmilleria windrow, oriented specimens on a small block retrieved
from the piles of the Pittsford Member from the Tastings Site. Note the wrinkled nature of
the preserved integument, a common condition observed within this unit. Desiccation of
the Silurian muds may be responsible for this type of preservaton.