Bluegrass, the mountains that you refer to and some others have fossilized seashells because at one time they were under a normal unflooded ocean and gradually came to be uplifted with the ocean being drained. If however there were to be a massive flood reaching up and over mountains in Turkey then the flood waters would have swirled around the mountains reaching much further out.
As far as the DNA being traced to one man that is a speciation event where a member(s) of a clan tribe or population has a mutant gene that differentiates him/her from the rest of the group and allows him/her to out reproduce the rest in due time. In essence, there is no such thing as a single man/woman event since there are always males and females of a "less evolved" type about to be replaced in the millenia that follow.
I suggest getting the book Science and Earth History by Arthur Strahler. It is specifically geared toward responding to Creationist beliefs and statements. At five hundred large size pages in fine print it is the most thorough book on the issues.
villabolo