Billings' second operculum: a late Early Ordovician Maclurites (Gastropoda) from western Newfoundland and the Canadian Arctic

1990 ◽  
Vol 27 (5) ◽  
pp. 669-676 ◽  
Author(s):  
Ellis L. Yochelson
Keyword(s):  
Functional Morphology ◽  
Growth Pattern ◽  
Canadian Arctic ◽  
Indirect Evidence ◽  
Ellesmere Island ◽  
Original Material ◽  
Early Ordovician ◽  
Sedentary Animal

An operculum of Maclurites, first described by Billings in 1865, is redescribed from the original material collected at Cape Norman, northwestern Newfoundland, and from additional specimens from Ellesmere Island, Canadian Arctic. Based on indirect evidence, a very late to latest Early Ordovician age is assigned to the strata of the St. George Group that contains this fossil. This operculum has a paleoequatorial distribution. On the basis of its geometry, the operculum is interpreted as having a "concentric" growth pattern rather than a spiral one. If so, the complex coiling pattern assumed for Maclurites may be in error. Speculation on functional morphology explains the shape of the operculum without recourse to any assumed coiling during growth and reinforces the interpretation of Maclurites as an exceedingly sedentary animal.

scholarly journals Stratigraphy and hystricurid trilobites of the Christian Elv Formation (Lower Ordovician) of western North Greenland

1989 ◽  
Vol 144 ◽  
pp. 5-15
Author(s):  
R.A Fortey ◽  
J.S Peel
Keyword(s):  
New Species ◽  
Shallow Water ◽  
Canadian Arctic ◽  
Ellesmere Island ◽  
The West ◽  
Early Ordovician ◽  
The North ◽  
Lower Ordovician ◽  
A New Species ◽  
North Greenland

The Christian Elv Formation (Early Ordovician) of Daugaard-Jensen Land, western North Greenland, is formally proposed and recognised from southern Hall Land, in the east, to western Ellesmere Island in the Canadian Arctic Islands, to the west. The formation in its type section includes a shallow water trilobite fauna suggesting a mid-Tremadoc age; conodonts indicate the Rossodus manitouensis Zone af the North American Midcontinent Realm. Two species af hystricurid trilobites are present, of which one, Hystricurus scrofulosus, is dcscribed as a new species. The distribution of Hystricurus followed the early Ordovician palaeo-equator and was not confined by palaeocontinental boundaries. Paraplethopeltis is considered to be a subgcnus af Hystricurus.

scholarly journals Fossils from the Poulsen Cliff Formation, Washington Land, western North Greenland

1982 ◽  
Vol 108 ◽  
pp. 24-24
Author(s):  
R.A Fortey ◽  
J.S Peel
Keyword(s):  
Canadian Arctic ◽  
Ellesmere Island ◽  
Early Ordovician ◽  
Stratigraphic Position ◽  
Cornwallis Island ◽  
North Greenland

The Poulsen Cliff Formation of Washington Land, western North Greenland, is a recessive, pale weathering unit, 100-125 m in thickness, of thinly-bedded dolomite, shale and sandstone witll conspicuous evaporites. The formation represents the continuation into Greenland of the lower part (member a) of the Baumann Fiord Formation evaporite sequence of the Canadian Arctic Islands, which outcrops over a distance of about 1000 km from Cornwallis Island to Ellesmere Island (Mossop, 1979; Peel & Christie, 1982; Peel, in press). The Poulsen Cliff Formation was first described by Troelsen (1950). It did not yield fossils to Troelsen but could with certainty be ascribed an Early Ordovician age on account of its stratigraphic position between fossiliferous units (Poulsen, 1927; Peel & Christie, 1982).

The first Tertiary (Paleocene) marine mollusks from the Eureka Sound Group, Ellesmere Island, Canada

1991 ◽  
Vol 65 (2) ◽  
pp. 242-248 ◽  
Author(s):  
Louie Marincovich ◽  
William J. Zinsmeister
Keyword(s):  
Atlantic Ocean ◽  
South Dakota ◽  
Arctic Ocean ◽  
Canadian Arctic ◽  
Ellesmere Island ◽  
Marine Mollusks ◽  
Molluscan Fauna ◽  
Northern Atlantic ◽  
Northern Alaska ◽  
Northern Atlantic Ocean

The gastropod Drepanochilus pervetus (Stanton) and the bivalve Cytrodaria rutupiensis (Morris) occur in the Mount Moore Formation at Strathcona Fiord, west-central Ellesmere Island, northern Canada. They are the first marine mollusks identified from the Eureka Sound Group of the Canadian arctic islands. These mollusks correlate with Paleocene faunas of the Cannonball Formation of North Dakota and South Dakota, the Prince Creek Formation of northern Alaska, the Barentsburg Formation of Svalbard, and the Thanet and Oldhaven Formations of southeastern England. These occurrences imply that the earliest Tertiary Arctic Ocean molluscan fauna was compositionally distinct from coeval faunas of the northern Atlantic Ocean.

scholarly journals The Wandel Valley Formation (Early - Middle Ordovician) of North Greenland and its correlatives

1988 ◽  
Vol 137 ◽  
pp. 61-92
Author(s):  
J.S Peel ◽  
M.P Smith
Keyword(s):  
Canadian Arctic ◽  
East Greenland ◽  
Middle Ordovician ◽  
Early Ordovician ◽  
Lowermost Part ◽  
North Greenland

Members are formally described within the Wandel Valley Formation (Early - Middle Ordovician) of the Ryder Gletscher Group in central and eastem North Greenland. In Peary Land the names Pyramideplateau Member (the combined lower and middle informal members of previous usage) and Vestervig Elv Member (the upper member) are proposed. In Kronprins Christian Land, the Alexandrine Bjerge Member (new) overlies the previously named Danmarks Fjord and Amdrup Members. Conodont studies, supported by the macrofauna, indicate that the Pyramideplateau, Danmarks Fjord and Amdrup Members are of late Canadian (Early Ordovician) age. The Canadian-Whiterockian boundary lies within the lowermost part of the Vestervig Elv and Alexandrine Bjerge Members. The top of the former is of earliest Late Whiterockian age while the Alexandrine Bjerge Member only extends into the late Middle Whiterockian. The members of the Wandel Valley Formation are correlated with coeval successions in western North Greenland, East Greenland, the Canadian Arctic Islands and Svalbard.

scholarly journals Natural and anthropogenic levels of tritium in a Canadian Arctic ice core, Agassiz Ice Cap, Ellesmere Island, and comparison with other radionuclides

2000 ◽  
Vol 46 (152) ◽  
pp. 35-40 ◽  
Author(s):  
Thomas G. Kotzer ◽  
Akira Kudo ◽  
James Zheng ◽  
Wayne Workman
Keyword(s):  
Ice Core ◽  
Canadian Arctic ◽  
Fission Products ◽  
Ellesmere Island ◽  
Anthropogenic Radionuclides ◽  
Ice Caps ◽  
Nuclear Bomb ◽  
Ice Cap ◽  
Nuclear Weapons Testing ◽  
Arctic Ice

AbstractNumerous studies of the ice caps in Greenland and Antarctica have observed accumulations of transuranic radionuclides and fission products from nuclear weapons testing, particularly during the period 1945–75. Recently, the concentrations of radionuclides in the annually deposited surface layers of Agassiz Ice Cap, Ellesmere Island, Canadian Arctic, from 1945 to the present have been measured and have demonstrated a continuous record of deposition of 137Cs and 239,240Pu in ice and snow. In this study, 3He-ingrowth mass spectrometry has been used to measure the low levels of tritium (3H) in some of these samples. Pre-nuclear-bomb tritium levels in ice-core samples were approximately 12 TU in high-latitude meteoric waters and 3–9 TU in mid-latitude meteoric waters. Comparisons of 3H levels and 3H/137Cs + 239,240Pu ratios, which were quite low during the earliest fission-bomb detonations (1946–51) and substantially higher during thermonuclear hydrogen-fusion bomb testing (1952–64), provide a clear indication of the type of nuclear device detonated. This finding accords with the results from other ice-core studies of the distribution of anthropogenic radionuclides from bomb fallout.

NOTES ON SOME ARCTIC COLLEMBOLA

1938 ◽  
Vol 70 (7) ◽  
pp. 151-154 ◽  
Author(s):  
H. G. James
Keyword(s):  
Canadian Arctic ◽  
Ellesmere Island ◽  
The Arctic ◽  
Baffin Island ◽  
Arctic Circle ◽  
Far North ◽  
Southern Shore

The following notes were made from a study of several species of Arctic Coollembola collected by Mr. W. J. Brown, of the Division of Entomology, Ottawa. Mr. Brown accompanied the voyage of the Canadian Arctic Patrol during August and September, 1935. During the trip he was able to collect on the southern shore of Baffin Island, and also well within the Arctic Circle as far north as Ellesmere Island.

Freboldia carinii sp. nov. from the Middle Triassic Brembana Valley (Esino Limestone, Southern Alps, Italy) – possibly the oldest known holoplanktonic gastropod

2020 ◽  
Vol 298 (1) ◽  
pp. 9-15
Author(s):  
Vittorio Pieroni ◽  
Alexander Nützel
Keyword(s):  
Life Style ◽  
Thin Shell ◽  
Type Species ◽  
Middle Triassic ◽  
Canadian Arctic ◽  
Southern Alps ◽  
Early Jurassic ◽  
Ellesmere Island ◽  
Gastropod Species ◽  
Mass Occurrence

A monospecific mass occurrence of the new gastropod species Freboldia carinii sp. nov. is described from the Middle Triassic Esino Limestone of the Brembana Valley, Southern Alps, Italy. It is the second species assigned to the genus Freboldia that was initially described from the Early Jurassic of Ellesmere Island, Canadian Arctic. This gastropod is unusual in being planispiral and inflated with a nearly bilateral symmetrical shape and in having a very thin shell. Like the Canadian type species of Freboldia, the new Triassic species is interpreted as a possibly holoplanktonic gastropod. If true, it would be the oldest known example of this life style in Gastropoda.

Early Ordovician to Early Devonian tectonic development of the northern margin of Laurentia, Canadian Arctic Islands

2019 ◽  
Vol 131 (7-8) ◽  
pp. 1075-1094 ◽  
Author(s):  
Keith Dewing ◽  
Thomas Hadlari ◽  
D. Graham Pearson ◽  
William Matthews
Keyword(s):  
Canadian Arctic ◽  
Early Devonian ◽  
Northern Margin ◽  
Early Ordovician ◽  
Tectonic Development

scholarly journals Chironomidae (Insecta: Diptera) from the eastern Canadian Arctic and subarctic with descriptions of new life stages, a possible new genus, and new geographical records

2016 ◽  
Vol 48 (2) ◽  
pp. 53 ◽  
Author(s):  
A. Namayandeh ◽  
K.S. Heard ◽  
E.A. Luiker ◽  
J.M. Culp
Keyword(s):  
Benthic Invertebrates ◽  
New Genus ◽  
Canadian Arctic ◽  
Ellesmere Island ◽  
Life Stages ◽  
Larval Form ◽  
International Polar Year ◽  
International Polar ◽  
A New Species ◽  
Eastern Canadian Arctic

Chironomidae larvae constituted the largest proportion of benthic invertebrates collected from 99 rivers stretching from northern Labrador (latitude 58°N) to northern parts of Ellesmere Island (82°N). We describe 92 species of Chironomidae (mainly larval forms) providing new descriptions, a revision for the adult female of <em>Parametriocnemus boreoalpinus</em> Gowin <em>et</em> Thienemann, a possible new genus (larval form only), and 9 larval forms that may represent a new species. In addition, new geographical distribution records are specified for 1 Nearctic species, 6 species in Canada, 10 for Labrador, and 17 for Nunavut. This work contributes to Environment Canada’s International Polar Year output (2007-2009).

HEXATYLUS MULVEYI N. SP. AND DELADENUS DURUS (COBB, 1922) THORNE, 1941 (NEMATODA: NEOTYLENCHIDAE) FROM THE CANADIAN ARCTIC

1964 ◽  
Vol 42 (4) ◽  
pp. 649-653 ◽  
Author(s):  
V. M. Das
Keyword(s):  
Northwest Territories ◽  
Canadian Arctic ◽  
Ellesmere Island ◽  
Single Line

Hexatylus mulveyi n. sp. and Deladenus durus (Cobb, 1922) Thorne, 1941, collected from soil in the Lake Hazen area of Ellesmere Island, Northwest Territories, are figured and described. H. mulveyi differs from H. viviparus Goodey, 1926 in the shape of the tail, the number of incisures, the single line of oocytes in the ovary, and in the vulva having elevated lips.

Sign in / Sign up

Export Citation Format

Share Document