Results 151 to 160 of about 29,037 (201)
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A giant Ordovician anomalocaridid
Nature, 2011Anomalocaridids, giant lightly sclerotized invertebrate predators, occur in a number of exceptionally preserved early and middle Cambrian (542-501 million years ago) biotas and have come to symbolize the unfamiliar morphologies displayed by stem organisms in faunas of the Burgess Shale type.
Peter, Van Roy, Derek E G, Briggs
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1978
Abstract Fission track analysis of pyrogenic apatite from a bentonite in the Acton Scott beds of the type section of Murchisons Caradoc Series has produced minimum ages of 443 ± 27 m.y. (external detector method) and 459 ± 27 m.y. (population method).
Reuben J. Ross +2 more
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Abstract Fission track analysis of pyrogenic apatite from a bentonite in the Acton Scott beds of the type section of Murchisons Caradoc Series has produced minimum ages of 443 ± 27 m.y. (external detector method) and 459 ± 27 m.y. (population method).
Reuben J. Ross +2 more
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1994
Abstract A number of new marine invertebrate faunas came into being in Ordovician times, and the generally rather monotonous features of the Cambrian biota were changed. Among the fauna were trilobites, graptolites, articulate brachiopods, nautiloids, and rugose and tabulate corals, which are of great significance in stratigraphical ...
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Abstract A number of new marine invertebrate faunas came into being in Ordovician times, and the generally rather monotonous features of the Cambrian biota were changed. Among the fauna were trilobites, graptolites, articulate brachiopods, nautiloids, and rugose and tabulate corals, which are of great significance in stratigraphical ...
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Geological Society, London, Special Publications, 1964
Summary Stratigraphical and palaeontological evidence for the location of the boundaries of the Ordovician System is examined and considered to be less important than historical priority, so that the Tremadoc is excluded from the system.
H. B. Whittington, A. Williams
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Summary Stratigraphical and palaeontological evidence for the location of the boundaries of the Ordovician System is examined and considered to be less important than historical priority, so that the Tremadoc is excluded from the system.
H. B. Whittington, A. Williams
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American Midland Naturalist, 1945
In 1936 Bradford Willard and the late Professor Freeman Ward collected graptolites from a dump at the Hess slate quarry number 22, at Lynnport, Lehigh County, Pennsylvania (1). The material was submitted to Dr. Rudolf Ruedemann for identification. Dr. Ruedemann noted certain arthropods among the graptolites and kindly consented to study the specimens ...
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In 1936 Bradford Willard and the late Professor Freeman Ward collected graptolites from a dump at the Hess slate quarry number 22, at Lynnport, Lehigh County, Pennsylvania (1). The material was submitted to Dr. Rudolf Ruedemann for identification. Dr. Ruedemann noted certain arthropods among the graptolites and kindly consented to study the specimens ...
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End Ordovician extinctions: A coincidence of causes
Gondwana Research, 2014The end Ordovician (Hirnantian) extinction was the first of the five big Phanerozoic extinction events, and the first that involved metazoan-based communities. It comprised two discrete pulses, both linked in different ways to an intense but short-lived glaciation at the South Pole.
Harper, David Alexander Taylor +2 more
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1993
Abstract Most Ordovician and Silurian rocks in western and northwestern Canada were deposited on the North American craton and its western continental margin. Strata of these ages have also been recognized in three allochthonous terranes in the Cordillera, described in the companion volume on the Cordilleran Orogen (Gabrielse and Yorath,
M.P. Cecile, B.S. Norford
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Abstract Most Ordovician and Silurian rocks in western and northwestern Canada were deposited on the North American craton and its western continental margin. Strata of these ages have also been recognized in three allochthonous terranes in the Cordillera, described in the companion volume on the Cordilleran Orogen (Gabrielse and Yorath,
M.P. Cecile, B.S. Norford
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Ordovician palaeogeography and climate change
Gondwana Research, 2021Trond Helge Torsvik, L Robin M Cocks
exaly