For reference, take a look at Google Maps, which shows the old roads and roads through the Range:
Beartown Road residents objected to the proposed changes in the zoning district boundary near the Range and the apparent conflict of interest that these changes represented.
At the 17 January 2013 Selectboard hearing on the zoning proposal, the Selectboard voted to remove the zoning districe boundary "snap" (my term) to the Range boundary.
At the 31 January 2013 joint meeting, Brad Holden, the Selectboard Chair explained that he had special knowledge of surveying issues in the area that caused him concern about the actual location of the Range boundary, and suggested that the Planning Commission might not really know where the existing zoning district boundary is.
Brad also talked about confusing horizontal datum. This appears to be a distraction to defuse the Planning Commissioners's confrontation and plumb the shallow depths of their research. The use of NAD27 vs NAD83 seems irrelevant. The Vermont State Plane is used for surveying and mapping. The kind of error that Brad has described does not seem possible as it involves geodetic coordinates.
This is a picture of part of Sheet 14 of the zoning map as of 1987, drawn on 1979 orthophotos, which are large scale, high resolution aerial photos projected onto the Vermont State Plane
Where the district boundary departs from the big curve on Beartown Road and continues in a straight line to the East, it clearly follows the road and driveway, not the range boundary, and not the stream.
It has been scoffingly mentioned by Planning Commissioners and the Zoning Administrator that "the original maps were hand drawn." Well, of course they were. Many great things were drawn by hand: the Washington Monument, Apollo spacecraft, Mount Rushmore. This is a fine map, drawn at a large scale of 1:5000. The printed GIS map of existing zoning is no better, and if you could see the aliasing of the straight lines in this map, you might say that it is worse than the "hand drawn" map. Much has been made about parcel boundaries. GIS mapping makes parcel boundaries appear more accurate than they actually are. In Vermont, surveying is by metes-and-bounds. Boundaries are by agreement. Parcel boundaries can move.