Portal de Periódicos da CAPES

On the Magog, Quebec, graptolites

1962; Yale University; Volume: 260; Issue: 2 Linguagem: Inglês

10.2475/ajs.260.2.142

1945-452X

William B. N. Berry,

Evolution and Paleontology Studies

Restudy of graptolite assemblages from the classic Castle Brook locality near Magog reveals that 2 graptolite zones, those of Climacograptus bicornis and Orthograptus truncatus var. intermedius, are present there. These zones indicate a late Middle Ordovician (Wilderness and Trenton) age for the rocks comprising them. If the graptolite-bearing slates are included in the Beauceville Group, the lower part of that unit is, therefore, Wilderness and Trenton in age. The graptolite-bearing rocks near Magog and the Normanskill Formation may be correlated because the same 2 graptolite zones are present in both units. The Magog graptolite-bearing strata are thus not younger than the Normanskill Formation, as has long been thought, and the graptolite fauna of the Magog rocks does not belong in a zone distinct from those in the Normanskill Formation.