Results 181 to 190 of about 34,448 (232)

Runcaria , a Middle Devonian Seed Plant Precursor

Science, 2004
The emergence of the seed habit in the Middle Paleozoic was a decisive evolutionary breakthrough. Today, seed plants are the most successful plant lineage, with more than 250,000 living species. We have identified a middle Givetian (385 million years ago) seed precursor from Belgium predating the earliest seeds by about 20 million ...
Gerrienne, Philippe, Meyer-Berthaud, B., Fairon-Demaret, Muriel, Streel, Maurice, Steemans, Philippe   +4 more
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Tioga Bentonite (Middle Devonian) of Indiana

Clays and Clay Minerals, 1973
AbstractThe petrography of shale partings in carbonate rocks from eleven cores in the Illinois (Jeffersonville Formation) and Michigan Basins (Detroit River Formation) of Indiana indicates the presence of a K-bentonite which is interpreted as the Tioga Bentonite, an important stratigraphic marker in the middle Devonian rocks throughout the central and ...
John B. Droste, Charles J. Vitaliano
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Middle Devonian stratigraphy of Indiana

Geological Society of America Bulletin, 1942
The Hamilton of Indiana consists of the Speeds, Deputy, Silver Creek, Swanville, and Beechwood formations, each with a distinct fauna. The lithology, range, and characteristic fossils of these formations and the Jeffersonville are given, and past errors of correlation discussed.
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Trilobite Taphonomy and Middle Devonian Taphofacies

PALAIOS, 1986
Detailed study of Middle Devonian trilobites from New York State indicates that taphonomic attributes are distributed nonrandomly among the strata and therefore may be used to characterize different taphofacies (i. e., facies defined on the basis of diagnostic taphonomic traits). Environments near normal wave base are represented by bioclastic deposits
Stephen E. Speyer, Carlton E. Brett
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Middle Devonian Unconformity in Michigan

Geological Society of America Bulletin, 1930
Introduction An unconformity or disconformity is usually discovered by carefully observing a zone of supposed contact and discriminating lithologically and faunally the beds above and below that zone. Nearly all the accepted disconformities have been discovered in this way.
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Lower Devonian-Middle Devonian Boundary in Central Nevada: GEOLOGICAL NOTES

AAPG Bulletin, 1962
New fossil collections from beds immediately overlying the long established "Spirifer" pinyonensis zone show that there is a complete faunal break between these horizons in the northern Roberts Mountains and in the northern Simpson Park Range, central Nevada.
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Early and Middle Devonian gastropod biogeography

Geological Society, London, Memoirs, 1990
Abstract Early and Middle Devonian gastropods show biogeographic patterns remarkably similar to those of better studied faunal groups of this same interval, notably articulate brachiopods, rugose corals, and trilobites. Three biogeographic realms are recognized: Old World, Eastern Americas, and Malvinokaffric Realms.
R. B. Blodgett, D. M. Rohr, A. J. Boucot
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Middle/Late Devonian Phoebodontbased ichthyolith zonation

Geobios, 1995
Abstract A subdivision of the upper part of the Devonian (varcus through praesulcata conodont zones) into six ichthyolith zones is proposed. The zonation is based on the stratigraphic ranges of elasmobranch teeth from the pelagic facies of Central and Eastern Europe. Species of the genus Phoebodus were chosen as index taxa.
Micha Ginter, Alexander Ivanov
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Middle Devonian Bentonite in Michigan Basin

AAPG Bulletin, 1974
The name "Kawkawlin Bentonite" is proposed for a thin subsurface bentonitic ash-fall bed in the Michigan basin Lucas Formation (upper Detroit River Group, Middle Devonian). Post-Detroit River emergence and erosion of the flanks of the basin resulted in truncation of the ash bed to its present limits.
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Scottish Middle Devonian fishes in Estonia

Scottish Journal of Geology, 2015
A number of Estonian Devonian fishes are shown to be junior synonyms of Scottish species. The Estonian sarcopterygian osteolepid Gyroptychius pauli was originally thought to be closely related to the Scottish species Gyroptychius milleri being differentiated by minor morphological differences
Michael J. Newman, Elga Mark-Kurik, Jan L. Den Blaauwen, Ivars Zupiņš   +3 more
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