Comments and Replies on “Three new Upper Cambrian stages for North America”

Geology ◽  
1985 ◽  
Vol 13 (9) ◽  
pp. 667 ◽  
Author(s):  
Rolf Ludvigsen ◽  
Stephen R. Westrop
Keyword(s):  
North America ◽  
Upper Cambrian

scholarly journals I.—History of the Names Cambrian and Silurian in Geology

1873 ◽  
Vol 10 (111) ◽  
pp. 385-395 ◽  
Author(s):  
T. Sterry Hunt
Keyword(s):  
Great Britain ◽  
North America ◽  
Upper Cambrian ◽  
History Of ◽  
Lower Palaeozoic ◽  
The Subject

It is proposed in the following pages to give a concise account of the progress of investigation of the lower Palæozoic rocks during the last forty years. The subject may naturally be divided into three parts: 1. The history of Silurian and Upper Cambrian in Great Britain from 1831 to 1854; 2. That of the still more ancient Palæozoic rocks in Scandinavia, Bohemia, and Great Britain up to the present time, including the recognition by Barrande of the so-called primordial Palæozoic; fauna; 3. The history of the lower Palæozoic rocks of North America.

Early Paleozoic Hyolitha from North America: reexamination of Walcott's and Resser's type specimens

1988 ◽  
Vol 62 (2) ◽  
pp. 218-233 ◽  
Author(s):  
John Mark Malinky
Keyword(s):  
North America ◽  
Lower Cambrian ◽  
Type Species ◽  
New Genus ◽  
Early Paleozoic ◽  
Type Specimens ◽  
Middle Cambrian ◽  
Upper Cambrian ◽  
New Family ◽  
The Family

Concepts of the family Hyolithidae Nicholson fide Fisher and the genera Hyolithes Eichwald and Orthotheca Novak have been expanded through time to encompass a variety of morphologically dissimilar shells. The Hyolithidae is here considered to include only those hyolithid species which have a rounded (convex) dorsum; slopes on the dorsum are inflated, and the venter may be flat or slightly inflated. Hyolithes encompasses species which possess a low dorsum and a prominent longitudinal sulcus along each edge of the dorsum; the ligula is short and the apertural rim is flared. The emended concept of Orthotheca includes only those species of orthothecid hyoliths which have a subtriangular transverse outline and longitudinal lirae covering the shell on both dorsum and venter.Eighteen species of Hyolithes and one species of Orthotheca from the Appalachian region and Western Interior were reexamined in light of more modern taxonomic concepts and standards of quality for type material. Reexamination of type specimens of H. similis Walcott from the Lower Cambrian of Newfoundland, H. whitei Resser from the Lower Cambrian of Nevada, H. billingsi Walcott from the Lower Cambrian of Nevada, H. gallatinensis Resser from the Upper Cambrian of Wyoming, and H. partitus Resser from the Middle Cambrian of Alabama indicates that none of these species represents Hyolithes. Hyolithes similis is here included under the new genus Similotheca, in the new family Similothecidae. Hyolithes whitei is designated as the type species of the new genus Nevadotheca, to which H. billingsi may also belong. Hyolithes gallatinensis is referred to Burithes Missarzhevsky with question, and H. partitus may represent Joachimilites Marek. The type or types of H. attenuatus Walcott, H. cecrops Walcott, H. comptus Howell, H. cowanensis Resser, H. curticei Resser, H. idahoensis Resser, H. prolixus Resser, H. resseri Howell, H. shaleri Walcott, H. terranovicus Walcott, and H. wanneri Resser and Howell lack shells and/or other taxonomically important features such as a complete aperture, rendering the diagnoses of these species incomplete. Their names should only be used for the type specimens until better preserved topotypes become available for study. Morphology of the types of H.? corrugatus Walcott and “Orthotheca” sola Resser does not support placement in the Hyolitha; the affinities of these species are uncertain.

Mass Extinction in the Cambrian Trilobite Faunas of North America

1990 ◽  
Vol 3 ◽  
pp. 99-115 ◽  
Author(s):  
Stephen R. Westrop
Keyword(s):  
North America ◽  
Distinctive Feature ◽  
Mass Extinction ◽  
Taxonomic Composition ◽  
Environmental Distribution ◽  
Profound Impact ◽  
Upper Cambrian ◽  
Cambrian Trilobite

Sepkoski (1981a,b, 1988) has characterized the Cambrian fauna as unique, both in terms of taxonomic composition and in environmental distribution of taxa. Compared with the rest of the Phanerozoic, the frequency of mass extinction in the Cambrian must also rank as a distinctive feature which had a profound impact on macroevolutionary patterns. Three well-documented extinctions occurred in the Upper Cambrian of North America (Figure 1; Palmer, 1979; Westrop and Ludvigsen, 1987) and are best expressed in the trilobite faunas. Possible older extinctions may be present at the top of the Olenellus Zone and near the base of the Bolaspidella Zone (e.g., see Palmer, 1982) but more data are required.

Biogeographic shifts in a transgressive succession: the Cambrian (Furongian, Jiangshanian; Latest Steptoean–earliest Sunwaptan) agnostoid arthropodsKormagnostellaRomanenko andBiciragnostusErgaliev in North America

2013 ◽  
Vol 87 (5) ◽  
pp. 804-817 ◽  
Author(s):  
Stephen R. Westrop ◽  
Jonathan M. Adrain
Keyword(s):  
New Species ◽  
North America ◽  
Sea Level Rise ◽  
Sea Level ◽  
Local Extinction ◽  
Faunal Turnover ◽  
Upper Cambrian ◽  
Extinction Event ◽  
Stratigraphic Interval

The first records of the upper Cambrian agnostoid generaKormagnostella, E. Romanenko,inRomanenko and Romanenko, 1967, andBiciragnostusF. Ergaliev,inEraliev and Ergaliev, 2001, in Laurentian North America are from a narrow stratigraphic interval in the Steptoean–Sunwaptan boundary interval (Furongian, Jiangshanian) of Nevada and Utah. In Nevada, both genera occur in a condensed bioclastic lag below a major flooding surface, andKormagnostellaalso appears in a transgressive interval in Utah. Immigration of these genera is associated with sea level rise, and also with faunal turnover.Biciragnostusis confined to the latestElviniaZone, immediately below the onset of a trilobite and agnostoid extinction event at the base of theIrvingella majorZone (basal Sunwaptan).Kormagnostellais present in the latestElviniaZone, and has its highest occurrence in theI. majorZone. Stratigraphic data from the Karatau-Naryn Terrane, Kazakhstan indicate that both genera disappear near the local extinction ofIrvingella, suggesting that faunal turnover in that region may have been broadly correlative with the more profound extinction in Laurentia. New species areKormagnostella advena,K. insolitaandBiciragnostus viator.

Trilobites, biostratigraphy, and lithostratigraphy of the Crepicephalus and Aphelaspis zones, lower Deadwood Formation (Marjuman and Steptoean stages, Upper Cambrian), Black Hills, South Dakota

2000 ◽  
Vol 74 (2) ◽  
pp. 199-223 ◽  
Author(s):  
James H. Stitt ◽  
Patrick J. Perfetta
Keyword(s):  
New Species ◽  
North America ◽  
South Dakota ◽  
Shallow Water ◽  
Black Hills ◽  
Strong Preference ◽  
Upper Cambrian ◽  
Shallow Subtidal ◽  
Intrashelf Basin ◽  
One New Species

Trilobites assigned to 25 genera and 39 species are reported from the Crepicephalus Zone (Marjuman Stage) and Aphelaspis Zone (Steptoean Stage) in the lower part of the Deadwood Formation in the Black Hills of South Dakota. Six taxa are left in open nomenclature, and one new species, Glaphyraspis newtoni, is described.Analysis of the lithologies for this interval from the best exposed measured sections on a southeast-northwest transect reveal a nearshore, shallow subtidal, siliciclastic dominated environment to the southeast, succeeded offshore by a shallow subtidal to lowest intertidal carbonate shoal environment, and then a transitional shaly limestone interval into a more shaly distal intrashelf basin to the northwest.Specimens of species of Coosia, Crepicephalus, Tricrepicephalus, Kingstonia, Pseudagnostina, and Coosina comprise more than 75 percent of the fauna of the Crepicephalus Zone. Coosina ariston, Crepicephalus snowyensis, Tricrepicephalus tripunctatus, Arcuolimbus convexus, and some species of Blountia had a strong preference for the shallow-water siliciclastic facies present in the southeastern sections closest to the paleoshoreline. Crepicephalus rectus, Tricrepicephalus coria, Agnostogonus, cf. A. incognitus and the genera Coosella and Uncaspis preferred the farther offshore, deeper-water, shaly intershelf basin located in the northern Black Hills. Trilobites from the Crepicephalus Zone are used to correlate the lower part of the Deadwood Formation with coeval strata elsewhere in North America.

scholarly journals Carbon isotopes, stratigraphy, and environmental change: the Middle–Upper Cambrian Positive Excursion (SPICE) in Port au Port Group, western Newfoundland, Canada

2018 ◽  
Vol 55 (11) ◽  
pp. 1209-1222 ◽  
Author(s):  
Rosalia Barili ◽  
Joyce Elaine Neilson ◽  
Alexander Thomas Brasier ◽  
Karin Goldberg ◽  
Tatiana Pastro Bardola ◽  
...  
Keyword(s):  
North America ◽  
Environmental Change ◽  
Carbon Isotope ◽  
Carbon Isotopes ◽  
Carbonate Rocks ◽  
Isotopic Signature ◽  
Upper Cambrian ◽  
Carbon Isotopic ◽  
Carbon Isotope Excursion ◽  
Diagenetic Environment

In many basins, Upper Cambrian carbonate successions display intervals with a positive carbon isotope excursion (CIE) of up to +5‰. In North America, this marks the boundary between the Sauk II–III super-sequences. A Steptoean positive carbon isotope excursion (SPICE) locality previously identified in the Port au Port peninsula, western Newfoundland, has been revisited and an additional potential SPICE locality found. In both locations, a CIE is found to be associated with a prominent bioherm and sandstone layer within a sequence of carbonate rocks. At March Point columnar stromatolites occur, whereas at Felix Cove thrombolites can be seen. In the latter, the sandstone immediately overlies the thrombolites coincident with the CIE, whereas at March Point a dolomitized grainstone occurs above the stromatolites. The sandstone at this locality post-dates the CIE. Although lower than the SPICE in some localities, a positive CIE is present in both sections: March Point (+1.1‰) and Felix Cove (+1.8‰). Additionally, δ13Corg rises from −30.0‰ to −22.0‰ at March Point and from −27‰ to −24.0‰ at Felix Cove and, in accordance with previously published work, we suggest that this could be the SPICE. Comparison of the stratigraphy and petrography between the two localities suggest that both depositional and diagenetic factors could have influenced the nature of the interpreted SPICE in Newfoundland. It is also possible that the local carbon isotopic signature may have been influenced by a semi-restricted depositional and early diagenetic environment related to the paleogeographic configuration rather than the global marine excursion.

Comments and Replies on “Three new Upper Cambrian stages for North America”

Geology ◽  
1985 ◽  
Vol 13 (9) ◽  
pp. 666 ◽  
Author(s):  
R. A. Robison ◽  
A. J. Rowell ◽  
W. H. Fritz ◽  
V. E. Kurtz ◽  
J. F. Miller ◽  
...  
Keyword(s):  
North America ◽  
Upper Cambrian

Three new Upper Cambrian stages for North America

Geology ◽  
1985 ◽  
Vol 13 (2) ◽  
pp. 139 ◽  
Author(s):  
Rolf Ludvigsen ◽  
Stephen R. Westrop
Keyword(s):  
North America ◽  
Upper Cambrian

Revision of certain Lower Ordovician Faunas from Ireland

1945 ◽  
Vol 82 (2) ◽  
pp. 55-66 ◽  
Author(s):  
F. R. C. Reed
Keyword(s):  
North America ◽  
Present Author ◽  
Western North America ◽  
General Aspect ◽  
The West ◽  
Upper Cambrian ◽  
Lower Ordovician ◽  
West Of Ireland

Since the publication of the papers by Messrs. Gardiner and Reynolds on the Tourmakeady and Glensaul districts in the west of Ireland, with palaeontological appendices by the present author, Raymond (1925, p. 167) has compared the faunas with those of Newfoundland and pointed out some striking resemblances. Other Lower Ordovician faunas have since then been described from various foreign regions, and in the light of this increased knowledge the specimens in the collections from Ireland have been re-examined; this has resulted in revised generic identifications, though confirming the reference of the beds to the Lower Ordovician as the author originally maintained (1910, p. 271). The trilobites, several of which are now put in other genera, are mostly allied to or comparable with species of the Canadian and Ozarkian of North America, Newfoundland, and Greenland which Poulsen (1937, p. 72) correlates with the Arenig and Tremadoc, and they also show resemblances to some of those of the Ceratopyge fauna (Brögger, 1896) of Europe and Western North America (Raymond, 1922) as well as with those of Newfoundland. The brachiopods, the determination of which had been found a matter of much difficulty owing to their poor preservation, possess affinities with many of the American Upper Ozarkian and Canadian species recently named by Ulrich and Cooper (1938), especially with those from Canada, rather than with any of the European forms with which they were previously compared or identified. The admixture of Upper Cambrian fossils with those of the Ceratopyge zone, especially in Nevada and the Mount Robson district, was noted by Raymond (1922, p. 20); and similar interrelations of the two faunas are also traceable in the present case. From the general aspect of the faunas from the Irish localities, Ulrich (1930, p. 19) was inclined to put the beds “about the middle or upper Chazyan”; Grabau (1935, p. 101), relying on the lists of brachiopods and trilobites in the present author’s original papers, would refer them to the Middle rather than the Lower Ordovician, but this view can no longer be held.

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