 Thomas Marshall 's paternal grandfather , Riley Marshall , immigrated to Indiana in 1817 and settled on a farm in what is now Whitley County . He became wealthy when a moderate deposit of oil and natural gas was discovered on his farm ; when he sold the farm in 1827 it earned $ 25 @,@ 000 , $ 474 @,@ 044 in 2009 chained dollars . The money allowed him to purchase a modest estate and spend the rest of his life as an active member of the Indiana Democratic Party , serving as an Indiana State Senator , party chairman , and financial contributor . He was also able to send his only child , Daniel , to medical school . 
