In general, as discussed elsewhere herein, a major limitation of remote mapping using VCGI as done for this report is that the method lacks the ability to discern vertical subsurface stratigraphic, structural, and textural differences. However, reports in the literature make reference to both oscillations and readvances. As discussed by Calkin, the distinction between a “readvance” and an “oscillation” is important but difficult to make. In general, the term “readvance” to me implies climatic significance, and should only be used when and where the evidence so indicates.
The T3/T4 and T8 ice margins are here regarded as indicating readvances. The evidence for a readvance of the T3/T4 margins comes from the correlation with the White Mountain Moraine System ice margins of Thompson et al. In the Missisquoi Basin, evidence of a readvance, which is here correlated with T8 ice margin and time was previously reported by Wagner(1972) and Cannon(1964). The scales of these readvances, meaning the distance that the ice margin readvanced is unknown. In the case of the T8 margin it appears that the recession following the T7 ice margin in Fort Ann time was sufficient to allow for the invasion of the Champlain Sea into the Missisquoi Basin prior to the readvance in T8 time, and that the readvance may have resulted in an elevated proglacial water body level. The elevation, nature, and extent of this raised water body are unknown.
In the pre-Addendum study the “readvance” evidence reported by Wright et al in the Charlotte area and by Connally in the West Bridport area was correlated with readvance evidence previously reported by Cannon and Wagner in the Missisquoi Basin, all in T8 time. However, the Addendum study instead found substantial evidence that the Charlotte and West Bridport evidence was instead caused by oscillations related to the lateral shear margin of the streaming and calving of the Champlain lobe. This underscores the need for care in regard to the interpretation of structural and stratigraphic features.