I had found the 1850 census with Augustin Steen living next door to Elias - I think this was the first I had seen his name, but I did not find the marriage for him.I also had not seen the Robt Steen in Pointe Coupee on the 1830 census (I had found Elias and Elizabeth) and the other info listed in my original inquiry.
Other than that, I cannot find any further information on Augustin other than the death certificate for Sidney Steen who died in September 26, 1913 in Iberia Parish, Louisiana.The person who gave the information (a G.L. Steen) indicated that Sidney's father was "Gustin Steen" who I am guessing is Augustin Steen.
I did find a couple of books that I had been looking for on the Steen family.From glancing through it, I think there is a good possibility that this Steen family is related to the family I am researching.I thought I would include the books in case anyone wanted to download them from the following sites:
"The Steen family in Europe and America: a genealogical, historical and biographical record of nearly three hundred years, extending from the seventeenth to the twentieth century (1900" Edition I