True. And I can add this:
"In the state census, mortality schedules were generally recorded for the years of 1855, 1865, and 1875. They are arranged by state, then by county, and then by political subdivision (township, city, etc.). These schedules can add "flesh" to the bones of ancestors and provide information about the communities in which they lived. These schedules may be the only record of death for some individuals, as many states did not require recording of deaths until the late nineteenth century.
Mortality schedules record deaths in the year preceding the taking of the census. For example, the 1860 mortality schedules include persons who died between June 1, 1859 and May 31, 1860. For each person, the following information is listed: name, age, sex, marital status if married or widowed, state or country of birth, month of death, occupation, cause of death, and the length of the final illness."
So she was in the Federal census mortality schedule. I have seen the ones for NY state for the earlier state censuses (which are too early), but you already found her in the site that you mentioned.