Early Cambrian stratigraphy in the North American Cordillera, with discussion of Albertella and related faunas,

Abstract

Canada Geological Survey Museum Bulletin No. 2. GEOLOGICAL SERIES, No. 17. VI. Early Cambrian Stratigraphy in the North American Cordillera , with Discussion of Albertella and Related Faunas.

Chemostratigraphic correlations across the first major trilobite extinction and faunal turnovers between Laurentia and South China

“…However, the nature of the boundary between the lower and middle Cambrian was obscure. Burling 8 recognized the extinction of the olenellids marked the “Lower-Middle” Cambrian boundary 9 . The abruptness of the extinction led Cambrian workers 53,77,78 to recognize this extinction event as the Olenellid Biomere boundary.…”

“…The international correlation of the traditional lower–middle Cambrian boundary has been exceedingly difficult primarily due to apparent diachroniety of the datum species used to define the boundary reflecting the endemic faunas. Traditionally, this boundary has been marked by the first appearance datum (FAD) of Paradoxides (and other paradoxidid trilobites) in western Gondwana, Baltica, and Siberia 1–5 , the last appearance datum (LAD) of Redlichia (and other redlichiid trilobites) in South China 6,7 , and the LAD of Olenellus (and other olenellid trilobites) in Laurentia 8,9 . However, it has become apparent that the FAD of Paradoxides is not synchronous in Gondwana 10–14 , and this boundary is earlier than either the LADs of Redlichia or Olenellus 15 .…”

The stratigraphic section in the vicinity of Eureka, Nevada

“…Antagmus sp. At the type locality of the formation at Pioche, Nev. (Walcott, 1908a;Westgate and Knopf, 1932), the Pioche as originally defined contains both Lower and Middle Cambrian faunas (Burling, 1914;Mason, 1936;Deiss, 1938). Some recent authors have therefore proposed to restrict the name Pioche to the Lower Cambrian portion of the formation and have used the new name "Comet shale" for the upper portion.…”

Cambrian Stratigraphy and Trilobites of Northwestern Montana

“…The fauna occurs in the upper part of the Gordon shale throughout the area but has not been recognized elsewhere in Montana. In 1914, Burling (1914 reviewed the evidence pertinent to the stratigraphic position of the Albertella fauna and concluded from his analysis that the age of the fauna was early Middle instead of Lower Cam brian. In 1916, Burling (1916, p. 469-472) discovered Albertella with a Middle Cambrian fauna on Mount Bosworth in the Cathedral formation (Fig.…”