I may be able to help a little bit. Your John Snow was married to my great grandmothers sister. Her name was always listed as Cassie, but I figured it had to be something longer :) Cassie's mom is listed on the paper I have as a Mary Matilda Martha Emaline Thornsberry and her dad was listed as Charles Edmund (some say edward) Blackhawk. His birth is listed as Oct. 4, 1815 in Montana. It is said he died Sept. 1915. There was like 40 years between him and Mary. BUT, that is as far as I can get too. I have been searching for years and have never gotten any farther, I am stating to think these people fell from the sky and just started having kids or something. Please let me know if you get this and if you have anything else . :)