I thought I'd make some notes on some of the articles I got from the library yesterday, in case anyone might be interested in getting hold of them. I'll stick to the more interesting ones I got, and try to keep the waffle to a minimum...
The first one is an article by John Carey that has some good food for thought in relation to origin or creation legends of Ireland. I've been compiling as many "creation" tales as I can find over at Tairis Tales, and Carey makes some interesting points here:
'Origin and Development of the Cesair Legend'
Éigse Volume 22 (1987)
Cesair is typically credited as being the first settler of Ireland, according to the Lebor Gabála Érenn. Sent west by her grandfather (Noah) in an the hopes of escaping the imminent Flood, she arrives with a bevy of women and only three men to go round. The women are divided between the three men, Cesair herself marrying Fintan mac Bochra. Eventually the Flood comes and those who haven't died already succumb to it - all except for Fintan.
The Lebor Gabála itself is an eleventh century tale but earlier versions of the invasion story can be found in other sources. The lost manuscript of Cín Dromma Snechta, which dates to around the eighth century, lists Banba as the first woman to settle Ireland (lending her name to it). The Chronicon Scotorum, meanwhile (drawing on an eighth or ninth century descendent of the 'Irish World Chronicle'), lists the first woman as 'Eriu or Berba or Cesair.' A version of Lebor Gabála in the Book of Lecan also glosses Cesair's name with .i. Eriu. All this means: earlier versions from around the eighth century probably had the name as Banba or Ériu (or Berba, who Carey later associates with the River Barrow), which then became associated with Cesair.
Carey then goes on to discuss the significance of the legend, with two different theories proposed by other academics being influential: On the one hand, Cesair isn't mentioned in some invasion schemes at all (e.g. Historia Brittonum), suggesting she was added in at a later date - perhaps in order to give Ireland's origin story Biblical roots. On the other hand, Macalister (who translated the LGÉ) and the Rees brothers suggested that Cesair is pagan in origin, her story being 'a tattered fragment of a Flood myth' (i.e. a native Flood myth, not related to the Bible), and that Cesair and Fintan are a 'cosmogonic pair'; part of a native creation story, in which the Flood occurs during the process of the world's manifestation.
In a wider context, Carey notes that there are several different flood stories associated with women (such as the Wave of Clidna) to be found in the dindshenchas tales, and that Cesair's story could have had its origins in a local legend that was adopted and adapted into a broader context for the purpose of the LGÉ. This is the crux of the argument, and so Carey partially agrees with Macalister and Rees in that there are pagan origins for the story, but "it should be emphasized that the story appears to be a local legend, with no necessary connection to traditions either of world deluge or of primeval migration - in other words, I am led to agree with those who see its presence in the invasion sequence as an artificial and secondary development." (p46)
The final point for consideration is the location of the tale: if Cesair's story did start out on a local level, then as it exists today doesn't really help to pinpoint the location. Carey suggests that the tale has undergone a lot accretion, which muddies the waters somewhat, but it ultimately has its origins in a Leinster legend - "in which Ladru and his two companions stole Berba, with the host of her attendant maidens, from the Otherworld. They returned to Ireland and divided the women into three companies at Commar na Trí nUisce, but were overwhelmed by an avenging flood-wave from the sea. The three groups of women were very possibly linked with the three river which meet at that spot." (48)