Linda,
My maiden name is Shearburns. They started out in Macoupin county (Palmyra and Carlinville) and some ended up in Alton. I don't have Carter Shearburn in my computer database, but you are most assuredly related. I've got some handwritten stuff my mother sent me, let me see if I can find Carter in there. My grandfather was Olen Otis Shearburn. He had a brother, Leonard Earl "Bud" Shearburn. He owned an ice cream factory in Alton. Don't know if this is the cousin "Bud" you are referring to or not. If we find a connection, I can share information on the family I have traced back into the 1700s in England. Pse email me at mamie1866@aol.com.