i am not familar with any da silva in guyana but i am fimilar with achille garnier. u see my greatgrather name is also Achille Adolf Garnier and he is from france. he was married to one Cecelia Nunes and they had four children, Achille Jr, Desmond, Mazi, Barbara.i have no information if he was devorced. if u have any information please contact me. good luck with your search!!!