As I have previously mentioned, the men in the Carey Haplogroup R1b Lineage 1 are part of the Irish Type III subclade. Until proven otherwise, I am going to assume that all are positive for SNP R-L226.
An interesting fact about the members of the Irish Type III subclade is that their DYS 464 sequence is almost always 13-13-15-17.
In fact, prior to the R-L226 finding, the 13-13-15-17 sequence was one of the markers used to determine membership in Irish Type III.
The Careys in Haplogroup R1b Lineage 1 stand out as the primary exception. Their DYS 464 sequence is consistently 13-15-15-17.
This anomaly offers us a great opportunity. There are very few men who are both Irish Type III and have the 13-15-15-17 sequence.
As time goes by, and more men are tested, we should be able to determine when and where this significant mutation came about within Irish Type III. Doing so should enable us to trace Thomas the immigrant's ancestry with much more specificity.
Update: November 23, 2013
GATA H4 is also an important marker for Carey Haplogroup R1b Lineage 1. All members of that group have a value of 12 for that marker. Kit # 80504 is incorrectly shown as 11; it should be 12, according the the spreadsheet on the Irish Type III website. Most other members of Irish Type III have a value of 11.
It would be nice to be able to query the entire FTDNA database for kits that are R-L226 positive, have the 13-15-15-17 sequence discussed above, and also have the value of 12 for GATA H4. Does anybody know a way to do that, or is that a capability reserved for certain privileged characters?