OK, Ive solved my mystery! The "Malison" Coolidge in the 1880 census, daughter of William & Charlotte (Van Dusen) Coolidge and the "Mrs. Andrew Cook", daughter of Charlotte (Van Dusen) Coolidge, in Charlotte's obit is Milissa S. Coolidge, born about 1867, wife of Andrew S. Cook. They had children Nellie H. Cook (1896-1904), Orra Cook (abt. b. 1891), Douglas Stephen Cook (b. 1894), and Mervil William Cook (b. 1899).