I've just been looking at Altons in County Limerick and my sources believe that the name in the Pfalz or Rhineland was first Altheimer, then Altimes, then Alton. A book called "The Irish Palatines in Ontario: religion, ethnicity and rural migration" by Carolyn A. Heald (Gananoque, Ontario: Langdale Press, c1994, 195 p.) seems to cover the emigration to Ireland, then to America pretty thoroughly. I say "seems" because so far I've only so far seen a few Xeroxed pages that have to do with the Altons.
1709 seems to be the magic year for the German Palatines to begin their move to Ireland, and about 1819 for the beginning of the now-Irish Palatines move on to America.
Where did you find one of the Altimes in 1710 and 1860, please? Does my information sync up with any of yours?