Can anyone tell me how the Barton family is related to Sir William Wallace?

I keep finding many correlation's between the Barton family and Sir William Wallace's (Brave heart) and I can not figure out how the Barton's and the Wallace's are connected. I think that it may be through his mother but I am not sure because at first I thought that she was a Barton but then found out that she was a Crawford, so what is the connection? HELP!!!!!