In looking at variations on family names, you might discover how the family tree extends to other branches that you may or may not suspect?
The root name seems to be "Clement" of French origin that crossed from Normandy to England. It is noted that both "Clemens and Clemm", could also be found in Northern New England in The United States. If there is a family tree connection... could "Mark Twain" be related to Poet-Writer, Edgar Allan Poe... by way of His Aunt and Mother-In-Law, Maria Poe-Clemm?
This opens some interesting Kin possibilities???
Mark Twain is my 4th cousin 12 times removed husbands 10th grt grandsonhttp://www.geni.com/path/Judy-Rice+is+related+to+Mark-Twain?from=60...
You seem to be more related to My Cousin/ExWife side to Mark Twain, Cousin. In truth... A portion of My Direct Cousins, personally met and directly knew Cousin Sam... Like My Direct Elder Cousin, "Joseph Henry Benrimo" etc.www.twainquotes.com/19060521.html
Though I never met Cousin J.H., I did meet His Sister, Donah Benrimo, whom I think met Cousin back then :)