I have a copy of the members of Co.I and there is liisted J. Tarkington as Pvt. in that company. I don't know if you live close to Liberty,Tx. but if he was from Liberty there is a very good research library(Sam Houston Research Center & Library)just out of Liberty on Hwy.146. They may have something on him. Good luck!! Wish I could have been more help !--Russell Jordan