How To Use Devonian In A Sentence

The Early Devonian saw a decline to 20 genera, with a slow return by the end of the Pragian, a tectonically active phase marked by global sea level drawdowns, and provinciality.
The fact that these rocks were not supplying detritus to the sedimentary basin is consistent with the geological observation that they always appear covered by the younger deposits, with little or no discontinuity until the Devonian.
In the Lower Devonian, ammonoids appeared, leaving us large limestone deposits from their shells.
The status of many Eurasian species of Late Devonian cyrtospiriferid brachiopods require careful restudy to properly assess their generic status and assignment to morphologic/phylogenetic groups of Cyrtospirifer outlined below.
Variably serpentinized Devonian mafic and ultramafic intrusive rocks occur in the western and northern parts of the map area.

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Fossilized spinnerets (the organs that spit out the spider silk) that occur in Middle Devonian rocks in Schoharie County, New York, show that spiders have been making silk for at least 380 million years.
The sequence comprises Lower Ordovician conglomerates and carbonates overlain by Upper Ordovician to Middle Devonian limestone with occasional phyllite and quartzite.
As an independent check on the overall oxygen trend, it is notable that fusain is found for the first time in the Late Devonian.
Certain ancient strata, known as the Devonian black shale, occupying the Ohio valley and the neighbouring parts of North America to the east and north of that basin, appear to be accumulations which were made beneath an ancient Sargassum sea. Outlines of the Earth's History A Popular Study in Physiography
The allochthonous units that overlie the eastern part of this terrane were probably emplaced when the Magnitogorsk volcanic arc collided with this margin in late Devonian times.
Many Devonian species differ from Early Carboniferous species in having quadrate rather than cuneate brachials and in having straight-sided rather than zigzag arms.
Older Palaeozoic rocks are represented by greenish grey slates from the sides of the Beardmore glacier and by radiolarian cherts; but the most widespread of the sedimentary rocks occurring in vast beds in the mountain faces is that named by Ferrar the Beacon sandstones, which in the far south Shackleton found to be banded with seams of shale and coal amongst which a fossil occurred which has been identified as coniferous wood and suggests that the place of the formation is Lower Carboniferous or perhaps Upper Devonian. Perspective of Antarctica in 1911
Now, this oil is found in what they call the Devonian limestone, and it is our first production from Devonian. An Amateur Looks at the Canadian Economy
Thus, this area shOuld belong to North China Region(otprovince )of the Old World Realm in respoct to reginalism of brachiopod zoogeography during lateEaly Devonian time.
During his stay at Kent State, Loren monographed the Devonian and Mississippian conulariids of North America, and described disarticulated conulariids.
Nonmarine occurrences of Rusophycus-like bilobed resting traces, widely recorded from Devonian to Permian subaqueous deposits, were probably produced by notostracan or phyllopod crustaceans.
As to fossil representatives of the ichthyic type, the most ancient were not supposed before 1838 to be of a date anterior to the Coal, but they have since been traced back, first to the Devonian, and then to the Silurian rocks. The Antiquity of Man
After publication of the palaeomagnetic results, other field studies have supported this hypothesis on the basis of palaeontology and stratigraphy and matching of Devonian palaeocurrents and structural patterns.
Presumably (assuming insects do derive from Crustacea) primitive hexapods evolved from marginal marine and amphibious crustaceans during the late Silurian or early Devonian.
The earliest described insects are flightless; they occur in Scottish Devonian rocks, and are similar to modern springtails.
They evolved in the Devonian, comprising evolute to involute planispirally coiled conchs quite similar to that of the contemporaneous nautiloids.
By the Early Devonian the Iapetus Ocean had closed and was replaced in northern Britain by an essentially transtensional regime with sinistral shearing, and accompanied by major igneous activity.
The coelacanths were a side group of crossopterygians who evolved along separate lines from the rhipidistians in the Devonian.
The first tetrapods, or land-living vertebrates, appeared during the Devonian, as did the first terrestrial arthropods, including wingless insects and the earliest arachnids.
Although there are no outcrops of Devonian extrusive volcanic rocks in NW Scotland, they can be found in southern and central Scotland and the Orkney Islands.
Huachanggou gold deposit locates in Guozhen Formation of Sanhekou Group of Devonian Mianxian - Lueyang suture zone.
Microbes and insects that first evolved in the Devonian will descend in force, and soon the rose garden is a flowerless patch of thorns. Earth Day: War of the roses
The Late Devonian - Middle Jurassic depositional systems in Fujian Province arereconstructed in the paper.
It was found that there exit paleo- reservoir in Devonian stratum, Tianjingshan structure, in course of investigation of oil - sand resource in the northwest part of Sichuan Basin.
The late Devonian also marked the first tetrapods - vertebrates with true legs that could walk on land.
The rebel Cornishmen, joined by sympathetic Devonians, marched on Exeter and laid siege to the City.
Variably serpentinized Devonian mafic and ultramafic intrusive rocks occur in the western and northern parts of the map area.
During the Devonian period, insects began to exploit terrestrial environments. Flight, the exoskeleton, and metamorphosis are probably keys to insect success.
At some point during the lower Devonian, the sea began to transgress again, and this continued through the deposition of the Port Ewen formation.
The heavily armored fish from the Devonian became extinct, being replaced with fish fauna that look more modern.
A Devonian CRM is interpreted to be related to hydrothermal fluids associated with Devonian volcanic rocks or to fluids triggered by late stages of the Caledonian orogeny.
The foregoing words and expressions are probably provincialisms rather than Devonianisms, good old English forms of expression; as are, indeed, many of the so-called Hibernicisms.
Dolostone septaria and iron sulfide nodules occur in the Late Devonian Huron Shale.
The site is particularly important in representing ichthyological fauna (fishes) of the Devonian period. Miguasha Provincial Park, Canada
By the end of the Devonian, ferns, horsetails and seed plants had also appeared, producing the first trees and the first forests.
Related agnathans with external armour occur widely from the Late Silurian to the Devonian, but they all became extinct before the start of the Carboniferous.
In addition to this technical difficulty, it was found that the Devonian synclinal, which is the geologic substructure of the region was disturbed by a tectonic anomaly in the form of a narrow band, less than one kilometer in width, which had become deflected in front of the Longlier valley, passing just under the terminal point where the construction of the railroad had stopped. Albert Claude - Autobiography
They were hit hard by the terminal Devonian extinction event, and most marine forms died out then, only the coelacanths continuing.
Jawless fishes and placoderms were also affected, although many placoderm lineages survived quite happily until the end Devonian.
This field of shagreen is limited to a strip along the dorsal lip of the prearticular and the denticulated texture of the dorsal surface does not grade in from the mesial surface as in other Late Devonian tetrapods.
The northern margin of the fold-thrust belt is composed of sedimentary sequences of Middle to Upper Devonian and Carboniferous rocks.
Variably serpentinized Devonian mafic and ultramafic intrusive rocks occur in the western and northern parts of the map area.
The most persistent bed of nodules is found in the Late Devonian Huron Shale.
The catastrophe of the Late Devonian was roughly equivalent in magnitude to the event at the end of the Cretaceous that killed the dinosaurs.
In the southern half of the Caledonian orogen, sedimentation in the post-Caledonian continental basins started significantly earlier, in the Mid-Devonian.
Although there are no outcrops of Devonian extrusive volcanic rocks in NW Scotland, they can be found in southern and central Scotland and the Orkney Islands.
I remember when I first heard of diamictite: It was during a controversy in the 1980s about peculiar rocks in South America (Carboniferous or Devonian, I forget) that everyone had been calling tillite. About.com Geology
The researchers suggest that low global oxygen levels during this period, known as the Devonian, may explain the evolution of air-gulping characteristics. Dailyindia.com News Feed
The flora and fauna fossils of Miguasha are particularly important in representing ichthyological fauna (fish) of the Devonian period. Miguasha Provincial Park, Canada
Researchers from France, China and ESRF have identified enigmatic fossils from Devonian (400 million years) as fructification of charophyte algae. A Bit of Science, a Bit of Politics
Many paleobotanists believe that the earliest seed plants evolved from heterosporous Middle Devonian plants like the progymnosperms.
During the Late Silurian and Early Devonian, the Royal Creek area lay at the margin of a deep-water embayment.
The Cape Floristic Region overlies the Cape Supergroup, a Devonian-Ordovician series of sedimentary strata, where alternating quartzitic sandstones such as Table Mountain and the Witteberg Groups alternate with fine-grained shales, as seen in the Bokkeveld Group. Montane fynbos and renosterveld
Researchers from France, China and ESRF have identified enigmatic fossils from Devonian (400 million years) as fructification of charophyte algae. A Bit of Science, a Bit of Politics
Grotte Pere-Noel lies under woodland with a brown forest soil on Devonian limestones and dolomite.
Renewed work on the first known Devonian tetrapod, Ichthyostega, is showing that it, too, diverged from the norm— contrary to earlier preconceptions .
He recognized two different fossil fauna assemblages in the limestone and the divided the limestone into two distinct lithologic units of Devonian and Mississippian age.
The thick Thunderhead Sandstone (Upper Precambrian Great Smoky Group) in the Great Smoky Mountains along the Tennessee/North Carolina border was deformed and regionally metamorphosed during formation of the Appalachian Highlands, beginning in the so-called Devonian (that is, early in the Flood year).12-14 With increasing temperatures and pressures from northwest to southeast, the regional metamorphism produced in these sandstone layers a series of chemically and mineralogically distinct zones of schists and gneisses.15 These zones are named according to the first appearance of the distinctive metamorphic minerals which characterize them as the intensity of the metamorphism increased laterally—the biotite, garnet, staurolite, and kyanite zones. Ken Miller in Cleveland: WEBCAST ARCHIVE URLS - The Panda's Thumb
Benthic armored fish are common by the Early Devonian.
However, I also examined some other problematical specimens from the Early Devonian of Canada, first described as belonging to acanthodian fishes (named Doliodus), and discovered that they were really sharks' teeth as well.
During the Early Devonian two realms were separated by a ridge extending through the centre of the continent.
Such giant cephalopods play or played a similar ecological role of top predator to that of Devonian arthrodire placoderms, Mesozoic pliosaurs and Cenozoic toothed whales.
I gasped — for the fish had been a ganoid — that ancient, armoured form that was perhaps the most intelligent of all life on our planet during the Devonian era, but which for age upon age had vanished, save for its fossils held in the embrace of the stone that once was their soft bottom beds; and the half-globes were Medusae, jelly-fish — but of a size, luminosity, and colour unheard of. The Moon Pool
In the middle Devonian the first collembolans made their appearance, and by the Pennsylvanian, or late Carboniferous, winged insects were present, including the first mayflies and cockroaches.
The Cape Floristic Region is more-or-less coincident geologically with the Cape Supergroup, a Devonian-Ordovician series of sedimentary strata, consisting of alternating layers of quartzitic sandstones (the Table Mountain and Witteberg Groups) and fine-grained shales (Bokkeveld Group). Lowland fynbos and renosterveld
The entire north area consists of Quaternary sediments, while the surrounding uplands are dolostone, limestone, and sandstone of upper Silurian to lower Devonian origin, plus associated till.
The shaping of Qiyang arc and the development of Jura-type folds are resulted from the decollement between pre-Devonian basement and its cover under eastwest compressive stress field.
Minor glaciations may also have taken place in the earlier Ordovician early Silurian and late Devonian.
By the Middle Devonian the armoured jawless ostracoderms were in decline, and instead the jawed fish were undergoing a great evolutionary radiation in both the sea and in freshwater.
Large dolostone septaria and iron sulfide nodules occur in the Late Devonian Huron Shale.
By the Mid-Devonian, placoderms, the first jawed fish, appear.
Near the end of Devonian times, thirty percent of all animal life vanished.
The emergence of terrestrial vertebrates from fish in the Late Devonian was one of the most significant events in the history of life.
After publication of the palaeomagnetic results, other field studies have supported this hypothesis on the basis of palaeontology and stratigraphy and matching of Devonian palaeocurrents and structural patterns.
Overlying elastic material derived from the volcanic rocks is estimated to be of Late Devonian to Early Carboniferous age.
The bet was placed thousands of miles away in south-eastern United States, on a sandstone rock formation called Devonian shale. Reliance Drills Shale At Home And Abroad
Benthic armored fish are common by the Early Devonian.
This interpretation is also indirectly supported by the close stratigraphic occurrence (Early and Middle Devonian) of these gastropod genera having such an unusual gerontic aperture.
The other stowaway, whom I will call the Devonian -- it was noticeable that neither of them told his name -- had both been brought up and seen the world in a much smaller way. Essays of Travel
There is no microbial encrustation of the surface, as reported, for example, in Devonian palaeokarsts of the Canning Basin.
However, a range of volcanic ages from Lower Cambrian to Early Devonian is suggested on biostratrigraphic grounds.
If we are correct, the Late Devonian wood problem was an almost inevitable result of evolutionary developments at the dawn of life.
Nodules and crystal groups of iron sulfide of Middle Devonian to Pennsylvanian age are frequently present in beds of black shale and coal or, less commonly, dolostone.
The heavily armored fish from the Devonian became extinct, being replaced with fish fauna that look more modern.
I've been making my way through the September 2008 Journal of Paleontology, and so there was "A new desmatosuchine aetosaur (Archosauria; Suchia) from the Upper Triassic Tecovas Formation (Dockum Group) of Texas," "A juvenile skull of the primitive African ornithischian dinosaur Heterodontosaurus tucki from the 'Stormberg' of South Africa," and "The anatomy, affinity, and phylogenetic significance of Illemoraspis kirkinskayae (Osteostraci) from the Devonian of Siberia. "The lengths that I will go to, the distance in your eyes..."
That time, part of an interval of Earth's history called the Devonian Period by scientists such as geologists and paleontologists, is known popularly as the Age of Fishes.
In the meantime the Devonian temperature increased and desert areas expanded.
The bulk of underlying rocks (slates and greywacke to greenschist facies) are marine Silurian, Devonian and Carboniferous sediments of the Hodgekinson Basin and Broken River Embayment. Wet Tropics of Queensland World Heritage Site, Australia
Tulerpeton, from the Upper Devonian of Russia, is found in a deposit with a rich fauna of marine invertebrates.
In summary, examples of deviation from regular tight coiling during late shell stages and the development of a free gerontic whorl may be found in all known Cambrian-Devonian gastropod subclasses.
The first tetrapods, or land-living vertebrates, appeared during the Devonian, as did the first terrestrial arthropods, including wingless insects and the earliest arachnids.
Related agnathans with external armour occur widely from the Late Silurian to the Devonian, but they all became extinct before the start of the Carboniferous.
The main slivers of Devonian rocks found within the fault zone in the Rhynie area are sandstones and andesite in the Rhyme block and the Longcroft Tuffs in the Windyfield block.
Mixed Devonian and Mississippian conodont and foraminiferal faunas and their bearing on the Roberts Mountains Thrust, Nevada, CreationWiki - Recent changes [en]
Underlying the glacial deposits is approximately 330 ft of Devonian limestone and dolomite.
The oldest well-known fossil hexapod is called Rhyniella praecursor, a collembolan from the Early Devonian age Rhynie Chert.
The skulls of Devonian lungfish have a tessera of small superficial bones, fused to an ossified chondrocranium.

How To Use Devonian In A Sentence

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