Tectonic models of the Taconian orogeny in western New England must account for the rapid metamorphism of the Taconic klippen after thrusting. The most likely source of heat for this metamorphism is an overlying hot thrust sheet of accretionary wedge material, which overrode the continental margin of ancient North America, culminating in a continent-island arc collision. Thermal calculations indicate that rapid conductive heat transfer from such a sheet is possible. The dimensionless Peclet number suggests that conductive heat transfer is faster than, or operates at rates comparable to, advective heat transfer due to thrusting over a distance of at least 6 km from a thrust surface. Thus, syntectonic heating of footwall rocks below a major thrust surface is important and must be taken into account in tectonic models. The continental margin thrust system (CMTS) in western New England may have formed as a set of duplexes under a main roof thrust separating the CMTS from the overriding thrust sheet of accretionary wedge material and above a main floor thrust along which the CMTS was transported over autochthonous continental margin rocks. Thrust sheets in this system are composed of Middle Proterozoic Grenville basement and/or upper Proterozoic to Middle Ordovician cover rocks of a western shelf sequence or eastern slope-rise sequence. According to this duplex model, thrust faults tended to develop sequentially toward the foreland, in the transport direction. The relative timing of thrusting and metamorphism is an important constraint on tectonic models, but metamorphism is not a reliable datum with which to compare the timing of events in different parts of the thrust belt. As an example, synmetamorphic thrusting in the eastern internal part of the belt may have preceded brittle faulting to the west near the foreland. P-T paths of rocks from different thrust sheets separated by major faults will be qualitatively different, and detailed petrologic studies to determine and compare P-T paths from different thrust sheets may be useful in identifying faults along which the greatest displacement has occurred.