According to Thom, they were 'Type 1'  or 'Type 2' flattened circles. There were also elipses and various other interesting geometries. This particular circle is aligned to several major sites in the area, notably Priddy Circles - three earthworks nearby; and Stanton Drew triple stone circle, which is directly 45 degrees Notrtheast  from the centre of the Fernhill Farm Stone Circle. In March 2007 shaun discovered a very interesting alignment between the stone circle, Glastonbury Tor and the Woodhenge he built at the Sunrise Celebration site in 2006. See the image below.

The placement of the circle was carefully chosen because of the south-facing nature of it and the fact that a number of skylines could be seen from its centre. A natural placement for such a device to study the movement of the stars. The newly discovered alignment has helped us realise that perhaps the ancients intuitively placed the monuments 'where they were supposed to be', without resorting to complex surveying unless they really had to. Earth energies and ley lines are also present, but to get the facts on those, you have to come to Shaun's dowsing workshops and the lectures by members of The Antiquarian Society.