Something worth pointing out about Lettergorman, with regard to the quartz boulder. It has previously been noted, a belief held by the former owner, that the stone was probably moved in from the field, from a position either along the axis or in line with Carrigfadda.
However the stone has been in the same position since Windele's survey in the mid 1800's and when viewed from centre-circle crudely indicates the four stone grouping on the slope of Maulatanvally. An arrangement three-quarters composed of quartz.
Dating evidence, dependent on excavation and the retrieval of datable material, is scarce for the Cork-Kerry stone circle complex. Three ranges have however been produced and are as listed below:
(O'Brien, 'Aspects of Wedge Tomb Chronology' in Shee Twohig and Ronayne (eds.), 'Past Perceptions: The Prehistoric Archaeology of Southwest Ireland', 1993, 70).
An assumed date of about 1000BC for the construction of Lettergorman South would probably be reasonable and Clive Ruggles has calculated the Winter Solstice sunset declination at this time to be -23.8 degrees (Astronomy in Prehistoric Britain and Ireland, 1999, 57).
Unlike the excavation record the archaeoastronomical survey history of the complex is comparatively extensive, if frustratingly incomplete. Somerville made some initial investigation in the early years of the last century, but the first large survey, of 30 circles, was undertaken by John Barber in the early 1970's. He listed Lettergorman (Knockawadra) as -26.111 degrees, some 2.311 degrees, or over 4 diameters, off the solar event, and looked instead to the stars for an alignment ('The Orientation of the Recumbent-Stone Circles of the Southwest of Ireland', JKHAS 6, 26). In fact the only Winter Solstice alignment he confirmed was the well-known one at Drombeg.
At the start of the next decade, however, a correction to his data was published by Patrick and Freeman ('Revised Surveys of Cork-Kerry Stone Circles', Archaeoastronomy, no.5, JHA, xiv, 1983, 51) when their own survey revealed a systematic difference with that of Barber, a discrepancy which they proposed to have been caused by the metal in his theodolite and tripod. Their findings linked Lettergorman (Knockawadra) at -24.3 degrees to Drombeg (-22.68) in a duo demonstrating a midwinter sunset orientation.
This alignment is not widely known, even locally. A historian who lives a few miles away and has visited Knocks North for the Equinox and Drombeg for the Winter Solstice wasn't aware of it when I mentioned it to him recently, but Jack Roberts does seem to have witnessed it ('Exploring West Cork', 1988, 131).
Clive Ruggles was also attracted to this region's monuments, but only surveyed the multiple stone circles, publishing data for 31 sites ('Astronomy in Prehistoric Britain and Ireland', 1999, 217). A combination of the 2 sets of data means about 40% of the complex has now been accurately assessed, with three circles proposed to be in alignment with the Winter Solstice: Drombeg, Lettergorman South and Teergay (near Macroom).
In this respect Ruggles makes a slightly odd statement when he writes of Drombeg:
'Although much-heralded, the solar alignment is not repeated at a single other example of this type of monument'
(Ruggles, Prendergast and Ray (eds.), 'Astronomy, Cosmology and Landscape', 2001, 53)
Granted that he doesn't include five-stone circles in his assessment, he still has Teergay measured at exactly -23.8 degrees in his table of data? I'm sure I'm probably missing something...