Accuracy of these arms 

I would question the accuracy of these arms. 

Also, many of the arms below are entirely novel or recent innovations, replacing existing arms either formally granted to counties i.e. County Councils since the 1899 Local Government Act or since independence and arms associated with counties since time immemorial. As such, I reckon former  County Arms ought to be given, as well as modern emblems (Kerry and Armagh, to name but a few). 

Where no arms existed, the arms of the County Town was used: Castlebar for Co. Mayo, or Athlone for Co. Westmeath. I would indicate these with an example. 

Dates of formal adoption should be given also.

The arms of County Dublin I believe pre-date the 19th Century (I could be wrong) and I would indicate the Fingal, Dún Laoghaire-Rathdown and South Dublin are successors.