| From Rochester Academy of Science ABSTRACTS TWENTY FOURTH ANNUAL FALL SCIENTIFIC PAPER SESSION AT ST. JOHN FISHER COLLEGE, ROCHESTER, NEW YORK SATURDAY, NOVEMBER 8, 1997 |
| INTERNAL STRATIGRAPHY OF THE LATE SILURIAN PITTSFORD SHALE (VERNON FORMATION) AT THE WEGMANS SUPERSTORE SITE ALONG THE ERIE CANAL, PITTSFORD, NEW YORK Samuel J. Ciurca, Jr., 44 Stonington Drive, Pittsford, New York |
| The lower Vernon Formation of the Late Silurian Salina Group is the repository of immense numbers of fossil arthropods, brachiopods and pelecypods. The fauna of the Pittsford Member, first described by Clifton Sarle in 1903 from excavations in the Erie Canal near the Brighton-Pittsford town line, is of interest because it preceded the better-known faunas of the Late Silurian Bertie Group that extends nearly across the entire state. Temporary exposures of a portion of the lower Vernon Formation were available for study during the interval August 1996 through October 1997. Construction of a new Wegmans Superstore in Pittsford, New York (not far from the type Pittsford Shale behind the Spring House) necessitated extensive excavating, especially along the outer wall of the Erie Canal that was to form one of the main walls of the new superstore. The trench that was excavated (over 300 feet long by about 12 feet across and several feet deep) revealed an excellent section of the Pittsford Member of the lower Vernon Formation, superjacent waterlimes and redbeds and subjacent shales and dolomitic mudstones. As interpreted herein,the Pittsford Member consists of a complex 0f 80 cm. of dark grey and black mudstone and shale with intercalated lenticular and thin waterlime units and a resistant bed of dolostone near the middle. Upper beds are heavily mudcracked and eurypterid debris appears to have fallen into some of the cracks before being covered by the next sedimentary event. Of particular note are the lower 10 cm. These contain abundant impressions of halite crystals indicating the hypersaline conditions that existed during much, if not all, of the deposition that resulted in the formation of the Pittsford Shale. Ironically, this bed also contains arthropod trackways that are currently under study. Immediately below these black shales occurs the Clam Bed, a thin resistant dolostone containing abundant pelecypods. The Pittsford Member appears to contain eurypterid remains throughout. There also appears to be a decrease in the abundance of Hughmilleria socialis toward the top of the member and a corresponding increase in the occurrence of Eurypterus pittsfordensis. At least one "mass mortality" horizon occurs and was observed within the lower 15 cm. of the member. Work in progress will lead to an improved stratigraphic column of the lower Vernon Formation inclusive of the faunally important eurypterid-bearing units and a geologic map along the outer wall of the Erie Canal. The paleontology of beds overlying and underlying the Pittsford Shale is the subject of a paper currently in preparation. I wish to thank Carl A. Rosati of CME Associates, Inc. for access to the site so that I could measure the newly exposed strata, photograph the various units including the Pittsford Shale and collect various sedimentary structures and fossils. |
| From Rochester Academy of Science ABSTRACTS TWELFTH ANNUAL FALL SCIENTIFIC PAPER SESSION AT MONROE COMMUNITY COLLEGE, ROCHESTER, NEW YORK SATURDAY, NOVEMBER 2, 1985 |
| A NEW EURYPTERID HORIZON (MONROEAV BED) AT THE BASE OF THE VERNON FORMATION, SALINA GROUP, SILURIAN OF WESTERN NEW YORK STATE Samuel J. Ciurca, Jr., 48 Saranac Street, Rochester, New York, 14621 |
The basal strata of the Silurian Vernon Formation (Salina Group) in western New York contains an interval of
eurypterid-bearing black and variegated shales that is usually called "Pittsford Shale."
During the Spring of 1985, construction of a new onramp at Monroe Avenue and Interstate 590 South revealed
a section of strata close to the contact with the underlying Lockport Group. The newly observed strata is
unknown in natural outcrop and has only been noted in a core (see p. 103, Clarke & Ruedemann, 1912).
The newly exposed shales contain a profusion of Lingula sp. and represent, essentially, a Lingula Bed. Associated,
however, are rare eurypterid fragments including a swimming-leg joint and metastoma characteristic of the
eurypterid Eurypterus pittsfordensis known previously only from stratigraphically higher beds.
This newly observed Lingula-eurypterid bed is dark grey in color weathering to a light yellowish to greenish grey
and corresponds to the seven feet of strata just above the Lockport Group described in the above reference.
This bed is herein named the Monroeav Bed and is the lowest eurypterid horizon currently known in western
New York.
The stratigraphically higher "Pittsford Shale" horizon (Sarle, 1903) so well-known for its abundance of Hughmilleria
socialis is herein redefined as the Pittsford Bed with the type area being in the old Erie Canal behind the Spring
Houwe.
Additionally, an eurypterid horizon (another black shale) known for its abundance of E. pittsfordensis, and that
occurs 20-40 feet above the Pittsford Bed, occurs in the village of Pittsford along the Barge Canal. This bed is
herein name the Barge Canal Bed.
eurypterid-bearing black and variegated shales that is usually called "Pittsford Shale."
During the Spring of 1985, construction of a new onramp at Monroe Avenue and Interstate 590 South revealed
a section of strata close to the contact with the underlying Lockport Group. The newly observed strata is
unknown in natural outcrop and has only been noted in a core (see p. 103, Clarke & Ruedemann, 1912).
The newly exposed shales contain a profusion of Lingula sp. and represent, essentially, a Lingula Bed. Associated,
however, are rare eurypterid fragments including a swimming-leg joint and metastoma characteristic of the
eurypterid Eurypterus pittsfordensis known previously only from stratigraphically higher beds.
This newly observed Lingula-eurypterid bed is dark grey in color weathering to a light yellowish to greenish grey
and corresponds to the seven feet of strata just above the Lockport Group described in the above reference.
This bed is herein named the Monroeav Bed and is the lowest eurypterid horizon currently known in western
New York.
The stratigraphically higher "Pittsford Shale" horizon (Sarle, 1903) so well-known for its abundance of Hughmilleria
socialis is herein redefined as the Pittsford Bed with the type area being in the old Erie Canal behind the Spring
Houwe.
Additionally, an eurypterid horizon (another black shale) known for its abundance of E. pittsfordensis, and that
occurs 20-40 feet above the Pittsford Bed, occurs in the village of Pittsford along the Barge Canal. This bed is
herein name the Barge Canal Bed.
| GEOGRAPHIC DISTRIBUTION OF THE EURYPTERUS PITTSFORDENSIS EURYPTERID FAUNA, PITTSFORD SHALE, UPPER SILURIAN OF WESTERN NEW YORK STATE Samuel J. Ciurca, Jr. |
During the deepening of the Erie Canal in 1897-1898, Clifton J. Sarle discovered an unusual eurypterid fauna in
strata lying between the Lockport Formation and the typically red Vernon Shale (basal Salina Group). This strata,
usually referred to as the Pittsford Shale or phase, contains several eurypterid genera. Two forms, however,
characterize this interval, viz. Eurypterus pittsfordensis and Hughmilleria socialis. Because the Pittsford Shale is
usually never exposed, it is important to note any new occurrences of this stratigraphic interval.
Reinvestigation, during the past several years, shows that the Pittsford Shale is much more widespread in
occurrence than heretofore known. Several new localities were discovered. Many of these form a cluster around
the originally defined site, i.e. the Erie Canal excavation hehind the Spring House on Monroe Avenue. These
provided numerous specimens of Hughmilleria, and rarely, Eurypterus. Another new site several miles to the west
(near North Chili) revealed only the presence of the Eurypterus. This is also true of the new locality at 'Gananda'
several miles to the east. A study of numerous fragmentary remains collected my R. Hamell, and kindly given to
the author, and numerous other remains collected, indicate only the presence of Eurypterus. Both of these sites
show primarily a dark, black to greenish black, matrix.
It appears that both eurypterids occupied distinct habitats. Communication between the habitats, or at least
access to a common site of burial and preservation, is indicated by the presence of both Hughmilleria and
Eurypterus in some layers. Detailed study of the fossils obtained from these new sites is in progress.
strata lying between the Lockport Formation and the typically red Vernon Shale (basal Salina Group). This strata,
usually referred to as the Pittsford Shale or phase, contains several eurypterid genera. Two forms, however,
characterize this interval, viz. Eurypterus pittsfordensis and Hughmilleria socialis. Because the Pittsford Shale is
usually never exposed, it is important to note any new occurrences of this stratigraphic interval.
Reinvestigation, during the past several years, shows that the Pittsford Shale is much more widespread in
occurrence than heretofore known. Several new localities were discovered. Many of these form a cluster around
the originally defined site, i.e. the Erie Canal excavation hehind the Spring House on Monroe Avenue. These
provided numerous specimens of Hughmilleria, and rarely, Eurypterus. Another new site several miles to the west
(near North Chili) revealed only the presence of the Eurypterus. This is also true of the new locality at 'Gananda'
several miles to the east. A study of numerous fragmentary remains collected my R. Hamell, and kindly given to
the author, and numerous other remains collected, indicate only the presence of Eurypterus. Both of these sites
show primarily a dark, black to greenish black, matrix.
It appears that both eurypterids occupied distinct habitats. Communication between the habitats, or at least
access to a common site of burial and preservation, is indicated by the presence of both Hughmilleria and
Eurypterus in some layers. Detailed study of the fossils obtained from these new sites is in progress.
| eurypterid.us |
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