I'll second the comment that there is no substitute for doing your genealogical research. You really can't go by last names to determine origins.

I'll also comment that you must remember that your family tree is actually shaped like a tree with you as the single trunk. Many people make the mistake of following one line of a family. Their family tree then looks up-side-down. That is - here at the bottom are me, my brothers, sisters, and cousins. We all trace our lineage up to King Jim MCII.

When in fact you need to think of it as - Here is me. I have two parents. Who each have two parents, who each have two parents. etc. etc. Each generation gets wider and more interconnected.

If you go back one generation you have four grandparents. Go back five generations and you have 64 grandparents. You can trace your lineage through all 64 people.

OH, and by the way five generations only takes you back a little over 120 years. You are not even back to the American Civil War yet.