The Piermont allochthon revisited and redefined at its type locality: Discussion

Timms (2004) has presented a very restricted interpretation of an important structural feature in the New England Appalachians that I originally termed the Piermont allochthon and interpreted as a far-traveled Acadian thrust sheet (Moench et al., 1987; Moench, 1990). As described herein, subsequent mapping has led me to a very different conclusion that, whether right or wrong, is crucial to understand because it bears directly on how we interpret northern Appalachian tectonics for Late Ordovician to Early Devonian time (see also Billings [1992] and Moench [1992]). Figures 1 and 2 of this paper and 2 and 3 of Timms (2004), at the same scale, are vastly different depictions of stratigraphy and structure at the very southern tip of the Piermont “allochthon” (quotes mine), which I now term the Piermont-Frontenac parautochthon. Timms appears to have been unaware of my concurrent work in the area and the evolution of my understanding of the Piermont-Frontenac parautochthon since the 1990s, which is discussed below.