Hello, Jamie
Your email is most interesting. It may be that your gggrandfather is also my gggrandfather, but the wives are different. I have traced the Garniers in Jersey and the only Joshua Garniers I have found are fathers and sons, i.e., from the same family. So if your gggrandfather was Joshua from Jersey, we're talking about the same family. My Joshua was born in St. Helier September 9, 1830. He emigrated with his wife Elizabeth Coutanche (m. June 20, 1852; died London, Ont. 1890) and 10 children to London, Ontario in 1872. In Canada they had one additional daughter. I haven't been able to trace what happened to Joshua after Elizabeth's death, although there is a family story that he remarried. His second wife's name may be Kate. I know of at least three children from this marriage. One Albert and one Isabelle.
Fiona Chamel, whom you also emailed, is related but from a brother of my Josue. The problems come in that my gggrandfather (probably yours as well) has a son Josue (died in London, Ontario). There is also a Josue Jean Garnier (b. 1826) whose wife's name was Hepizabah. I show that he died in Jersey.
Do be in touch with more information. I'm very curious as to what happened to my gggrandfather after Elizabeth's death. Do you have a death certificate for him?
Looking forward to hearing from you.
Diane