I am descended from William Kelton, via his daughter Esther (m. 1869 Robert Harvey). A very shadowy figure - left few traces! I think he had a sister Margaret, who witnessed Esther Kelton's marriage cert., and there was an "M. Kelton" on the "Orleana" of 1839. Margaret had an ilegit. child to one of Adelaide's founding father, Capt. John Duff, then married a George Robertson. William's wife is still a mystery, but there is a possible illegit. child to Barbara Richie at MacLaren Vale. I have patched together a few other likely children of his. I feel William and Margaret must be related to your John K., but for various reasons I don't think they were siblings. (Margaret's father was a John K., but not yours - perhaps a brother of Thomas K., your John's father?) Do you have any input into these mysteries? I'd love to hear from you if would like to reply.