Family on p. 23, Genealogy of William Tobias Phillips. On page 10, Elza has Mahlon's date of birth as 1830; on p. 23, he has it as 1831. There is no mention of Mahlon and Nellie being twins, so 1830 seems more likely.

1860 census of Floyd Co., Virginia, Indian Valley township, enumerated 1 Aug, lists on p. 133 as family #963/899:
Mahlon Phillips, 30; Rachael, 26; Eliza J., 6; Francis M., 4; Mary E. 1. All born in Virginia.

1870 census of Floyd Co., Virginia, Indian Valley & Burks Fork district, enumerated 27 Aug, lists on p. 32 as family #212/200:
Phillips, Mahlon, 45; Rachel, 37; Eliza Jane, 16; Francis M., 13; Mary E., 11; Rene A. (f), 9; Robert J., 7; Noah C., 3; Sarah E., 1. All born in Virginia.