In Manhattan births, there is a Marjorie P. Alger born Oct. 28, 1900.
Stewart C. Alger married Josephine Pershall on July 14, 1896 in Manhattan.
I see Stewart, Josephine and Marjorie in the 1910 census in Manhattan. By the 1920 census, Josephine is a widow, living with Marjorie.
In the Oct. 6, 1919 NY Times, there is a death notice for Stewart. He died at the home of his brother-in-law, Robert M. Dunn, in Newark, N.J., on Oct. 5, 1919.
Also in the NY Times, April 14 and 15, 1925, Josephine died at East Orange, N.J. on April 13, 1925. Survived by daughter, Marjorie Alger DuBois.
In the 1930 census for East Orange, Marjorie and husband Bernard DuBois, are the parents of Joan and Robert.
Good luck!