Quite possible that Mabel was also Mary Tripp's daughter......
1901 Census of Canada Page Information District: ON TORONTO (West/Ouest) (City/Cité) (#118) Subdistrict: Ward/Quartier No. 4 B-42 Page 10
Harvey Walter B. M Head M Oct 19 1869 31 Harvey Mabel F Daughter S Sep 18 1895 5 Trip Mary F Domestic S Sep 16 1868 32
018321-06 (Simcoe Co.) Walter Venn HARVEY, 39, Whitby, Toronto, inspector, s/o Henry HARVEY & Sarah VENN, married Mary TRIPP, 39, Allenwood, same, d/o James TRIPP & Matilda RITCHIE, wtn: Mary A. BROWN & Mary BROWN, both of Elmvale, on October 10, 1906, at Wyevale