My Buckmans originated in Sussex, I do not know of a Samuel or Rosina in my family. My gg-gfather, Jabez Buckman, was born in Lewes, Sussex in 1818 and was the 5th of 6 children. Other known children were Gideon, Ruth and there was a John. I have noted that this John Buckman migrated to Australia aboard the vessel "Amelia Thompson" arriving in Sydney on 1 July 1838. This is the only info I have I hope it helps.