S.M. Austin is Samuel McConnell Austin, born around 1794 in New Hampshire. He had three children by his first wife, Abigail Martin: Mary Ann Austin, Moses T. Austin, and Hannah Austin. His second wife was Mercy Miner, and by her he had "Pa" (nick name for Samuel McConnell Austin II), and also William Harvey Austin, Edward J. Austin, and Hiram Austin.
Information is still coming in and this will be expanded, especially after examination of an unindexed manuscript in late Summer 2011, on Austins in Wisconsin.