You didn't specify whther the Welch family was living in Overton Co. when she was born etc. but in the 1850 census there was only one welch family in the Co. Samuel 48 and Nancy 43 with the following children: Catherine 20; Emeline 17; William 17; John 16; Jacob 13; James 11; George 9; Hannah 7; Sarah 5; and Anne 2. Polly was a common nickname, generally for Mary but sometimes used for others also. In the 1880 census I only found one William Elmore in TN. He was born in 1847 but his wife's name was Martha and I believe they were in Jefferson Co., TN. The 1860 Census for Overton Co. is also on Roots Web TNGenWeb Project website but does not have an index so you would have to go page by page thru the images looking for the family. Don't know if this is any help or not. --- Rex Phillips