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Morphological, taphonomical, and sedimentological data from lower Llandovery fossils and strata of Anticosti Island demonstrate that the Virgiana community occupied a wide range of substrate settings from near or above fair-weather wave base to well below normal storm wave base. Globally the large-shelled pentamerid brachiopod genus Virgiana had a relatively short temporal duration during the early Llandovery (Early Silurian) and a wide geographical distribution in shallow carbonate basins of the paleocontinents of Laurentia (North America) and Siberia. In most areas, shells of Virgiana are found in post-mortem assemblages associated with ripple-marked and cross-stratified carbonate sands, indicating that they occupied carbonate banks and shoals above fair-weather wave base, and were subject to reworking during storms. Most species of Virgiana developed a costate shell with thickened ventral umbo and flattened apex, which probably helped the organisms stay in an incurved beak-down feeding position in current-swept environments, by weighting and stabilizing the shell posterior. Virgiana shells of the Becscie Formation of Anticosti Island are most commonly preserved as post-mortem assemblages in sharp-based, poorly graded packstones, as disarticulated, broken, nested, stacked, or imbricated valves. They are intimately associated with hummocky cross-stratified carbonate sandstones and massive to laminated mudstones, indicative of deposition by storm-induced current in mid-shelf settings, below fair-weather wave base. While some of the shells may have been washed in from shallower, inner-shelf environments during storms, many articulated specimens show well-preserved growth lines, and little evidence of abrasion, indicating local origin. The rare occurrences of in situ shells suggest that Virgiana communities extended into depths of 30 m. A further departure from the norm occurs in the overlying late Rhuddanian Merrimack Formation of Anticosti Island, where strongly costate, articulated shells of Virgiana mayvillensis are relatively well preserved in calcareous and micritic mudstone and calsisiltite beds. This suggests that V. mayvillensis was able to survive in deeper-water, relatively low-energy environments, in mid- to outer-shelf settings well below normal storm wave base. On Anticosti, there are no reefs in either of the Virgiana-bearing formations.

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GeoRef, Copyright 2018, American Geological Institute.<br/>1998-073354<br/>Becscie Formation<br/>Merrimack Formation<br/>Virgiana