Hi Ruskie,
I use Google Earth because it lets me zoom around more easily, quickly plug in lats and longs for locations (and saves them for me!), and use some drawing tools to, for example, draw in property lines if I know them. If anyone is interested I can show a jpg example of a a map I was creating of some old family-held land when a research colleague emailed me that he was in Nova Scotia and wondered how far he was from Black Brook Lake. I fired up Google Earth, brought up my image and drew a straight line the lake to his location and told him which roads would get him there.
Back to Tealan: Yes, I am sure it is a close as can be. Click your 12:18 link again. At bottom right it will show an NH number, and lat/long. As you move your cursor around, they both change to indicate your new location. I was exactly at NH526475 when I noted the location and used a screen capture to grab the map I show in my 23:11 message. It is not off by more than a few meters, I am sure. It shows a different NH number on the image, but the cursor necessarily moved when I went to select my screen capture tool.
Go ahead and try this using the Historical Overlay Maps from NLS
and one of the NH locations from the Simon Taylor dissertation.
Nick