Hi Joanne,
We must be cousins! I also have Queens County CLAXTON ancestors: Maria CLAXTON of Corbally married John O'BRIEN at Roskelton in 1855. Their first three children [including my g-grandfather James Wall O'BRIEN born in Colchester, ENG] were born before they migrated to Tasmania, where more children were born. We met the Blackhills family back in the 1970s when researching in your part of the world. I'd love to exchange more info with you.