Can Welsh ancestry be determined by surnames?

[tokareva]

I have no known Scottish ancestry but feel the need to justify wearing the kilt. Since there are some Welsh tartans, that hopefully might be the excuse I'm looking for. I have ancestors with the name Pritchard which is supposed to be of all Welsh origins also Wallen supposed to be 75% probability of being Welsh,but most sites say Swedish is the origin. Most of the family names seem to be of English origins, Keyes, Grills, Vickers, Pafford, Whittle, Johnson, and possibly Roberts that is also supposed to be Welsh.

Supposedly I'm related to Sir Thomas Overbury, could someone please confirm this and tell me of any possible Scottish or Welsh ancestors? On this document at 185. X. Ellis Newman Pafford is my Great Grandfather. Thank you.

http://johnniewbrown.net/Bluehost/Overby.html

Pritchard tartan