I recently bought Rathcroghan – Archaeological and geophysical survey in a ritual landscape by John Waddel, Joseph Fenwick and Kevin Barton, Wordwell Books. It was about 40 Euros when first published but I got it for a tenner in Chapters bookstore in Parnell St. in Dublin.

At the moment I'm reading (with difficulty) the introduction and there's an explanation of the various geophysical technologies that were used in the survey: Ground Penetrating Radar, Electrical Resistivity Tomography and Magnetometry.

All very fascinating but it got me to wondering – would any of these technologies, or other newer ones, be of any use in finding out if these: http://www.themodernantiquarian.com/site/1557/seefingan.html http://www.themodernantiquarian.com/site/2302/knocknarea.html http://www.themodernantiquarian.com/site/1043/heapstown.html and http://www.themodernantiquarian.com/site/3297/ballymacgibbon.html are actually passage graves and not just piles of stones like this: http://www.themodernantiquarian.com/site/7096/cairn_d.html

And if it is viable, should these important sites be surveyed? Or left alone? And if say Maeve's cairn was shown to be a passage grave, should it then be opened and excavated, to allow us to learn more (if there is more to learn in this narrow field)?