Hello,
I can't help with the tartan, but I can provide a little information regarding crests.
There seem to be two crests -- English and Irish.
If you look at our sister sites
http://www.daltongensoc.com &
http://www.daltondatabank.org, you will see both versions at the top of the page.
Here is a little description of the English crest:
“Azure semee of Crosses Crosslet de lis a lion rampart guardant argent.”
When translated the Brazon also describes the original colors of the Dalton Arms as:
“BLUE; STREWN WITH SILVER CROSSES CROSSLET; A SILVER RAMPANT LION, FACING FORWARD.”
