The Gander Lake and Davidsville Groups of Northeastern Newfoundland: New Data and Geotectonic Implications: Discussion
The results of recent structural and stratigraphic studies by Kennedy and McGonigal (1972) in the southeastern marginal zone of the so-called Central Paleozoic Mobile Belt in Newfoundland (Williams 1964) are to be welcomed as a new attempt to analyze and understand the nature of this complex zone and its role in the Appalachian edifice as a whole. It is of particular importance that these authors have discerned three major divisions of different characteristics in the broad belt of rocks known as the Gander Lake Group (Jenness 1958). These divisions however, which are described as "The Gneissic Terrane", "The Metasedimentary Terrane", and "The Sedimentary and Volcanic Terrane", substan tially differ in definition from the Lower, Middle, and Upper Units that had informally been distinguished in the Gander Lake Group by Jenness ( 1 963). Feeling confident that at least two of their new divisions are valid rock-stratigraphic units, whereas those of Jenness were not, Kennedy and McGonigal (1972) then proceeded to express this in formal nomenclature introducing a new name, Davidsville Group, for their sedimentary and volcanic terrane and r~defining the old name Gander Lake Croup to apply only to their metasedimentary terrane: whereas their gneissic terrane was left unnamed pending the outcome of further work. Considering the preliminary character of Kennedy and McGonigal's study, one may well hesitate to share their confidence in the validity of the stratigraphic units they have named formally, and indeed Jenness ( 1972) expresses serious doubts for several geological reasons. However, the writer does not wish to become involved in the discussion of the geology but finds it necessary to point out that Kennedy and McGonigal's restriction of the name Gander Lake Group to only one of three major divisions comprised in this group under its former definition is a clear violation of article 14(b) of the "Code" of the American Commission on Stratigraphic Nomenclature ( 1970), which states: