Here are a couple of maps for two surnames that first appeared at a relatively late date. Goad is probably a variant spelling of Coad. It was first recorded in 1638 at Menheniot but didn’t start appearing in the registers in any number until the 1670s when it suddenly turned up in multiple locations. Gribell or Grible was found at Sancreed in West Penwith from 1584 although the first record of the name was well to the east, at Bodmin.
You can find maps of these in 1861 for comparison here.
Remember, if you want information on a surname that hasn’t appeared in my book or been a subject of a previous blog do let me know.