morphologies (sample JC-10). (C) In the Erwin Formation, Mn and Fe oxides are deposited along existing bedding planes in quartzite. (D) Mn oxides in the Erwin Formation are frequently deposited as dendrites up to 1 mm in diameter (sample SH-1).

Figure 7. Backscattered scanning electron microscope (SEM) photomicrographs from breccia fills and bedding planes of the Shouns Prospect and Erwin Formation showing (A) the surface of Erwin Formation sample SH-1 (hand sample shown in Fig. 5D ) with Mn oxide dendrites surrounded by a rind

) sheets; (C) breccia matrix of sample SH-2 from the Erwin Formation showing goethite-coated filaments and (D) microlayered romanèchite interbedded with goethite.

; Cnt. H.lands, Central Highlands; CV, Catoctin Formation; DS, Dalradian Supergroup; EF, Erwin Formation; ES, Eleonore Bay Supergroup; FdL, Fleur de Lys Succession; GBS, Glen Banchor Succession; KG, Kong Oscar Fjord Group; KS, Krummedal succession; LbG, Lynchburg Group; LG, Labrador Group; MR, Mount

Formation, northwestern United States. (D) Montney Formation, British Columbia, Canada. (E) Toad Formation, southeastern Yukon Territory, Canada. (F) Werfen Formation, Dolomites, southern Italy. Modified from Pruss et al., 2004 ; after Erwin, 1993

Figure 1. Late Permian–Early Triassic paleogeographic map (modified from Erwin, 1993 ) showing global distribution of Early Triassic wrinkle-structure–bearing strata. Numbers indicate approximate locations where Early Triassic wrinkle structures were formed and preserved: (1) western United States

in Waggoner ( 1999 ); ( 3 ) Quercus pollardiana -type leaf from the Trapper Creek Formation, Idaho (UCMP #8605); ( 4 ) Quercus pollardiana -type leaf from the Fingerrock Formation, Nevada (UCMP #191949). All scale bars=5 mm. Images courtesy of D. Erwin.

Figure 1. Generalized distribution of chert from Late Archean time to present. Compiled from Maliva et al. (1989) , Siever (1991 , 1992) , Kidder and Erwin (2001) , Perry and Lefticariu (2003) , Kidder and Mumma (2003) , and Maliva et al. (2005) . The estimated frequency distribution

onward (recovery interval 2), species are increasingly restricted to particular niches because of competitive exclusion from neighbouring habitats. Recovery interval 2 ends when all curves level off. Logistic growth of alpha-diversity is adopted from Erwin (2001 ). The data from the Dinwoody Formation

Figure 3. Cr Isotope data from shale and iron-rich chemical sediments through time. Shown are Cr isotope data from shales (blue) of this study and Frei et al. (2011 , 2013 ), Gueguen et al. (2016) , and Wille et al., (2013) , and Cr isotope data from iron formations and ironstones (red

Fig. 8.  Probability plots of latest Neoproterozoic to early Palaeozoic metasedimentary units from along the Appalachian–Caledonian orogen in East Laurentia. Sources of data: Central Appalachians (Unicoi, Erwin, Hardystron formations), Eriksson et al . (2004) ; Eastern Blue Ridge–Piedmont

FIGURE 1 —Late Permian/Early Triassic paleogeographic map (modified from Erwin, 1993 ) showing the global distribution of Lower Triassic strata bearing abundant microgastropods. Data are from the literature. Numbers on the map indicate the approximate location where numerous microgastropod

Figure 21. Archaeichnium haughtoni Glaessner, 1963 , Huns Member, Urusis Formation, UCLA 7309, Arimas farm ( 1 ), UCLA 7325, Holoog River ( 2 ), and Neiderhagen Member, Nudaus Formation, Kyffhauser farm ( 3–6 ). ( 1 ) Four longitudinally striated individuals with pointed terminations (arrows

Figure 22. Coarsely and regularly annulated tubes, cf. Calyptrina striata Sokolov, 1967 ( 2–6 ), smooth tubes ( 1, 7 ), and two important specimens of Archaeichnium haughtoni Glaessner, 1963 ( 8, 9 ) from the Neiderhagen Member, Nudaus Formation, UCLA 7320, Kyffhauser farm ( 1–4

) , Yochelson (1956) , Batten (1958) , Winters (1963) , Erwin (1988 a , b , c ), and Batten (1989) . This fauna includes fossils of Wolfcampian, Leonardian, and Guadalupian ages. Larger gastropod and microgastropod species from 18 superfamilies (Pleurotomariacea, Euomphalacea, Trochonematacea, Trochacea