The Elizabeth Adams you mention is my GGGGrandmother. She married Flemming Franklin Cummins in 1840 and was the daughter of John Adams and Catherine Sampson Adams. I too have seen a file that contains a John Quincy Adams Jr. and Sr. but I think It is incorrect. The only John Q. Adams I have found in Garrard Co. records and Adams family cemetery records was born 19 Nov. 1811 and died 21 Feb. 1865. He married Angelina Walden in 1841. My John was married to Catherine in 1812 so they could not be the parents of John Lewis if he was born in 1811 but there is one record of an earlier marriage of a John Adams to Susanna Childress in 1804.Maybe my John was married twice? Hope this is some help.