The Silurian Eurypterid Fauna
Samuel J. Ciurca, Jr.
Rochester, New York
|A Land of Glacial Deposits and
Rolling Hills, Pittsford, and most of
Western New York, is a
Product of the Last Great Ice Age
Pittsford is a land of glacial deposits. The rolling hills are, generally, composed of sand and gravel left behind by the activity of the last great Ice Age--with a thin veneer of soil and vegetation covering the entire region. What we now see was formed during the last 10-25 thousand years.
Long,long ago, about 420 million years ago, this region was tropical with great reefs (bioherms) and expansive tracts of coral and sponge banks (biostromes) distributed across western New York State. The rocks that describe this phase of prehistoric time can be seen along area expressways near the Can of Worms, the I-490 rockcuts on the west side of Rochester and in area rock quarries. These rocks are part of the Lockport Group of dolo- stones of various textures and grain sizes: a lithostratigraphic unit about 150-200 feet in thickness. The Lockport Group underlies almost all of the Town of Pittsford. These rocks are exceedingly resistant and part of this rock unit is responsible for the resistant caprock that forms Niagara Falls.
Above the Lockport Group of dolomitic rocks, ie. reef and shelf carbonate deposits, occurs the varicolored shales and fine-grained dolostones of the Vernon Formatiion. In the Syracuse region, the Vernon Formation is about 600 feet thick, but the unit thins westward toward Pittsford. The formation consists primarily of redbeds with intercalated thin units of black and green shales and dolomitic mudstones
Apparently, a great complex of deltas spread outward toward upstate New York from what is now Pennsylvania during the Late Silurian time. Concom- mitantly, the reefs and the bulk of marine organisms were retreating westward toward the midcontinent.
Eurypterids (you-rip-ter-ids), fossils of which are locally abundant, were swimming by the millions in transitional environments--probably not the open sea--perhaps in shallow lagoons behind the receding reefs and in bays (Eurypterus?) and even in the rivers (Hughmilleria?) emptying into bays and lagoons. The sediments in these lagoons and bays were muddy and later were transformed into shales, ie. rocks formed from various kinds of very fine sediments, mostly clays. Some layers of thin waterlime that occur inter- bedded among the shales were, I believe, formed by stromatolitic activity in very shallow water of high salinity.
Many animals, including the eurypterids, were compressed by the enormous weight of incoming sediments into the fossils found in the rocks underlying Pittsford today. The entombed animals are now black because all that remains is the carbonized (black) residue of their shells (exoskeletons). The rock is also black because of the abundant fine carbonized (decomposed) organic material distributed throughout the matrix (ie. the rock surrounding the fossil).
COPYRIGHT 2000 Samuel J. Ciurca, Jr.
|Hughmilleria socialis Sarle|
|Clifton J. Sarle described, in 1902-1903, the discovery of prehistoric animals - arthropods found during the excavation of the Erie Canal near the Spring House in Pittsford, New York. These animals are the subject of most
of this website.
CLIFTON J. SARLE?
| WHEN PITTSFORD LOOKED
LIKE THE PLANET MARS !
410 million year ago, Pittsford was a very different plance. It may have looked like this.
|Fossils of the Pittsford Shale|
and the Erie Canal
|Samuel J. Ciurca Jr.|
|A small display of Silurian fossils can be viewed at the Pittsford Community Library. The display, photo at right, is the result of recent discoveries at various construction sites in the Pittsford area. On exhibit are examples of the two eurypterids described in the article on this page, as well as drawings of the fossils and samples of the rock types associated with this important fossil occurrence at Pittsford, New York. The modern HORSESHOE CRAB, a relative of the eurypterids, is also on display.|
|"Prehistoric Pittsford" at the Pittsford Community Library
Pittsford, New York just southeast of Rochester, New York.
Contributors are gratefully acknowledged:
Steve Hamm, Steve Jarose, Joseph LaRussa, and Tod Clements
|Pittsford Community Library
24 State Street, Pittsford, New York 14534
|ABOUT THE AUTHOR|
|Geologist Sam Ciurca, Jr. of Rochester, New York, started his interest in geology by going into the field looking for fossils and studying the rocks that contained them. He later went to college to study geology, chemistry and biology with an emphasis on the geolgoy and botany. He was interested in early (Silurian) land plants and especially in learning everything there was to know about EURYPTERIDS, what they were and where they could be found. The unusual rocks eurypterids are found in became of most interest--so he has studied the distribution in great detail--the stratigraphic occurrences and fossils and the sedimentary structures found within the "eurypterid beds."|
|At the left, the author, March 2001. The small eurypterid, Hughmilleria socialis, described in this website, is climbing up onto his shoulder and indicates the relative size of this species. At Pittsford, the remains of Hughmilleria occur by the millions, especially on certain bedding planes. However, glacial drift prevents access to most occurrences.|
|There is more to "Prehistoric Pittsford" than the famous eurypterid fauna discovered by Clifton Sarle (1903). Just 10 to 25 thousand years ago, ice ruled the region with a great continental ice sheet, a mile or more in thickness, that changed the landscape forever. Check out Ice Age Landscape by clicking the textframe to the right--------->|
|Ice Age Landscape
The story of Prehistoric Pittsford, when Pittsford and most of Upstate New York was covered by great sheets of ice over a mile in thickness.
|I COULDN'T STAND IT ANY LONGER, SO I SHOT MYSELF-DEAD- WHAT WITH THE NIGHTMARES AND ALL. I DID BECOME FAMOUS, HOWEVER, AND A FOSSIL WAS NAMED AFTER ME. WHO AM I? 200 YEARS LATER? WHAT DOES THIS HAVE TO DO WITH "Prehistoric Pittsford?"
F I N D O U T!
|INFO ABOUT ROCHESTER @Rochester Web DirectoryINFO ABOUT ROCHESTER|
|Rochester, New York & Suburbs: Please check out: http://www.rochesterinfo.com|
|OTHER PAGES ON THIS SITE ADD TO THE INTERESTING STORY OF PREHISTORIC PITTSFORD AND THE ERIE CANAL. CLICK THE LINKS BELOW:
How Are Fossils Named The Historic Erie Canal Erie Canal 2 Ice Age Landscape
|BENEATH OUR FEET|
|Once you get beneath the grass, the layer of soil, a varying thickness of sand and gravel, you reach BEDROCK. Pittsford Geology starts with the bedrock below the town--what it is and how it relates to the discovery of the Pittsford fossils. CLICK "Pittsford Geology" for additional insight. And, by the way, how far is it from the Pittsford Town Hall to the center of the earth? Everything we see occupies less than the first layer of an onion.|
|"Prehistoric Pittsford" Copyright 2000-2001 Samuel J. Ciurca, Jr. and the Town of Pittsford|
|Website Designed By
Samuel J. Ciurca, Jr.
54 Appleton Street
Rochester, New York 14611-2510
|GREAT FOSSIL SITES
Starting June 10, 2001, I began to list websites I've visited that compliment this site by providing information on paleontology. Interest in fossils is worldwide. After visiting the pages on this website, please check out the sites listed below.
|DARWINIANA & EVOLUTION
Links to Our Past
|GRUPPO NATURALISTICO PALEONTOFILO (Italian) with music "Hotel California."
|Eastern Missouri Society For Paleontology
|PALEOWEB IN ITALY|
|SITE MAP - TABLE OF CONTENTS|
|Eurypterids Eurypterid Structure Fossil Names Pittsford Fossils Ice Age Landscape
Pittsford 410 Million Years Ago Pittsford Geology Pittsford Pterygotid
Erie Canal Erie Canal 2 Erie Canal 3
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