James Robertson of Middlemarch Nz American Civil War Veteran

I am looking for information on the life, death and burial of James Robertson of Middlemarch who died July 24. 1927. I am told on his tombstone it reads Militiaman from the American Civil War. I would like to acquire enough information to add him to the Veterans Memorial website, www.acwv.info. Any assistance you can provide would be appreciated. jamesmgray@bigpond.com

Thank you.

James Gray