A friend of mine told me,
I have a Great aunt who was on the 1880 Mortality Schedule that I knew about and I just found two children from the Michigan 1870 schedule, that had not been recorded any where else, both were infants whose births were not registered.
Mortality schedules list people who died during the previous 12 months. Mortality schedules were taken along with population schedules during the 1850, 1860, 1870, and 1880 censuses, and in six states (Colorado, Florida, Nebraska, New Mexico, North Dakota, and South Dakota) in 1885. These schedules include persons who died between June 1st through May 31st in the year prior to the federal census. A typical mortality schedule will list the dead person’s name, age, sex, color (white, black, or mulatto), married or widowed, birthplace, month of death, occupation, and cause of death. Though part of the federal censuses, mortality schedules are separate from the population schedules.
The 1850 – 1885 schedules can be found at ancestry.com (indexed with original image ).
The 1850 schedules can be found at familysearch.org (free indexed with original image). And there is a transcription of the most counties mortality schedules at http://www.mortalityschedules.com/