Since the census was taken late (16 Aug), it is not clear if Mary was still living as of the census date or was included because she was alive on 1 Jun 1860, the official enumeration date.
Mary Aldridge, age 18, born in Virginia, murdered in July.
This has been indexed as Jul 1859. The mortality schedule was supposed to be for the year ending Jun 1860, but since the census was taken in Lawrence in Aug 1860, it looks like deaths up until Aug 1860 were included in the mortality schedule.