The Caleb Quarry History
The Middleport Quarry was a world famous source of Silurian Age invertebrate fossils from the Rochester Shale. Long before the excavation project started in the early 1990's, the fossil beds of the Lewiston Member of the Rochester Shale were made famous from the work done by James Hall in the 1850’s to 1860’s, Eugene Rinueberg in 1888 to 1890, Frank Springer in 1911 to 1914, and by Denis Tetreault, Wendy Taylor and Carlton Brett in the 1980’s. As a result of their work and others, the ancient environmental setting, depositional history and spectacular fauna specimens that were collected made the Rochester Shale of western New York and Ontario, Canada widely known.
It is now generally accepted that unique environmental and biological conditions existed to create perfect conditions for fossilization of several sequential ocean bottom communities of invertebrates. Geological evidence suggests that these communities existed in relatively shallow water below the effects of normal wave action, which was favorable to life. Carlton Brett describes that environment in the book, The Silurian Experience. For years the shallow ocean bottom remained full of life with the animals carrying out normal life cycles. Trilobites molted their shells, brachiopod shells separated after death, and scattered pieces of bryozoans, crinoids and cystoids were mixed in with other shell debris. This normal condition was periodically interrupted when large storms, perhaps hurricanes, churned up the sea floor. These storms would generate strong waves that would create great clouds of sediment that rolled across the sea floor for many miles, smothering the existing bottom communities. Any animals not able to escape the deluge of mud were quickly killed and buried. As a result of rapid burial, delicate fossils such as crinoids, cystoids and starfish remained intact, and in most cases out of the reach of scavengers. Moreover, since the smothered ocean floor was below normal wave action, it remained undisturbed from further reworking by waves and currents. Eventually the next generation of sea animals would re-establish normal sea bottom conditions only to be destroyed when the next large storm passed through these communities. This cycle of life and death would repeat itself more than a dozen times in the Rochester Shale as indicated by the fossil rich beds referred to as the Lagerstatten beds.
Prior to the Middleport Quarry, access to the Rochester Shale was limited to a few exposures across western New York and Ontario, Canada. Many of the outcrops are difficult to access and in all cases are mainly vertical exposures with limited opportunities to be excavated horizontally. Any fossils recovered from these sites were considered extremely rare and highly prized.
With the commercial excavation at the Middleport Quarry, more than ten acres of the Upper Lewiston Member was exposed. As a result of careful observations and exploration during the early years of the project, the famous Lagerstatten storm beds were identified.
For years four main smothered bottom communities were excavated horizontally along an east to west strike for approximately 750 feet, and removing beds southward for approximately 600 feet. As work progressed, ten additional Lagerstatten beds would be discovered and excavated horizontally. It is this shear volume of rock that has been worked to produce the large quantity and wide variety of fauna specimens now seen. Arctinurus and other fossil fauna would still be considered extremely rare if not for the dedicated work of the group at the Middleport Quarry.
Much of what we know regarding the geology and stratigraphy of the Rochester Shale has been documented over the past 100 years. In the 1980's, work done on the Rochester Shale in western New York by Carlton E. Brett, sub-divided the lower Rochester Shale (which he named the Lewiston Member) into five sub-members labeled s A, B, C, D, and E. The A sub-member is the lowest with E is the highest. These five sections represent cycles of the fossil and non-fossil bearing environments with this fossiliferous limestone beds scattered throughout.
Sub-members A and E are characterized by brachiopod and bryozoan-rich limestones while sub-members B and D are characterized by storm generated bryozoan-rich mudstones and include Lagerstatten beds, especially in transitions to and from Unit C. Intervals B and D are separated by sub-member C, which consists mostly of non-fossiliferous shale and silty limestones.
Based on Dr. Brett's work along with the groups findings, it has been determined that the exposure in the quarry ranges from the uppermost part of sub-member B through the upper part of sub-member E.
As work progressed over the years, specific beds rich in an array of fossils within these sub-members were identified. To reference them, each bed was named based on the dominance of one particular fossil common in the bed. For instance the "Dalmanites bed or the cystoid bed". For a detailed listing of the significant fossil beds is shown in the quarry stratigraphy chart.
It is now generally accepted that unique environmental and biological conditions existed to create perfect conditions for fossilization of several sequential ocean bottom communities of invertebrates. Geological evidence suggests that these communities existed in relatively shallow water below the effects of normal wave action, which was favorable to life. Carlton Brett describes that environment in the book, The Silurian Experience. For years the shallow ocean bottom remained full of life with the animals carrying out normal life cycles. Trilobites molted their shells, brachiopod shells separated after death, and scattered pieces of bryozoans, crinoids and cystoids were mixed in with other shell debris. This normal condition was periodically interrupted when large storms, perhaps hurricanes, churned up the sea floor. These storms would generate strong waves that would create great clouds of sediment that rolled across the sea floor for many miles, smothering the existing bottom communities. Any animals not able to escape the deluge of mud were quickly killed and buried. As a result of rapid burial, delicate fossils such as crinoids, cystoids and starfish remained intact, and in most cases out of the reach of scavengers. Moreover, since the smothered ocean floor was below normal wave action, it remained undisturbed from further reworking by waves and currents. Eventually the next generation of sea animals would re-establish normal sea bottom conditions only to be destroyed when the next large storm passed through these communities. This cycle of life and death would repeat itself more than a dozen times in the Rochester Shale as indicated by the fossil rich beds referred to as the Lagerstatten beds.
Prior to the Middleport Quarry, access to the Rochester Shale was limited to a few exposures across western New York and Ontario, Canada. Many of the outcrops are difficult to access and in all cases are mainly vertical exposures with limited opportunities to be excavated horizontally. Any fossils recovered from these sites were considered extremely rare and highly prized.
With the commercial excavation at the Middleport Quarry, more than ten acres of the Upper Lewiston Member was exposed. As a result of careful observations and exploration during the early years of the project, the famous Lagerstatten storm beds were identified.
For years four main smothered bottom communities were excavated horizontally along an east to west strike for approximately 750 feet, and removing beds southward for approximately 600 feet. As work progressed, ten additional Lagerstatten beds would be discovered and excavated horizontally. It is this shear volume of rock that has been worked to produce the large quantity and wide variety of fauna specimens now seen. Arctinurus and other fossil fauna would still be considered extremely rare if not for the dedicated work of the group at the Middleport Quarry.
Much of what we know regarding the geology and stratigraphy of the Rochester Shale has been documented over the past 100 years. In the 1980's, work done on the Rochester Shale in western New York by Carlton E. Brett, sub-divided the lower Rochester Shale (which he named the Lewiston Member) into five sub-members labeled s A, B, C, D, and E. The A sub-member is the lowest with E is the highest. These five sections represent cycles of the fossil and non-fossil bearing environments with this fossiliferous limestone beds scattered throughout.
Sub-members A and E are characterized by brachiopod and bryozoan-rich limestones while sub-members B and D are characterized by storm generated bryozoan-rich mudstones and include Lagerstatten beds, especially in transitions to and from Unit C. Intervals B and D are separated by sub-member C, which consists mostly of non-fossiliferous shale and silty limestones.
Based on Dr. Brett's work along with the groups findings, it has been determined that the exposure in the quarry ranges from the uppermost part of sub-member B through the upper part of sub-member E.
As work progressed over the years, specific beds rich in an array of fossils within these sub-members were identified. To reference them, each bed was named based on the dominance of one particular fossil common in the bed. For instance the "Dalmanites bed or the cystoid bed". For a detailed listing of the significant fossil beds is shown in the quarry stratigraphy chart.