The following chart shows the Counties that participants say their earliest ancestors came from. This shows the origin of the cluster appears to be somewhere in the counties of Clare, Limerick or Tipperary.
My paper, A Set of Distinctive Markers Defines a Y-STR Signature for Gaelic Dalcassian Families, proposing that the origins of Irish Type III are Dalcassian has been published in the Spring 2009 edition of Journal of Genetic Genealogy, www.jogg.info
It is available for download at www.jogg.info/51/files/Wright.pdf
The data supporting this paper can be downloaded from:- Supplementary Data.