Having done extensive research on Sandy and Mary Ann's decendants Its great that someone else points this out. I noticed that too! I am the great granddaughther of their dau Mary Jane Morrison who married my great grand father Mathew Alston in Maxton, Robeson Co. NC 1898.
I do not know what happened to Mary Jane Morrison or her husband Mathew Alston as all but one of their five children can be seen living with thier paternal grandmother Mary Johnson Alson-Taylor or Mary Taylor in the 1920 Census in Alfordsville, Robeson County, NC.
I have checked with the Robeson County Recorder of Deeds office and they don't have any record of Mary Jane Morrison and or Mathew Alston dying there, This is a huge mystery and I estimate that they died between 1910 and 1915, but can't find any records to substantiate it.
I was of course very thrilled when Frank found what he thought at first was Sandy and Mary's daughters, but neither were their dau May Jane Morrison.
I do plan to do further research on Sandy" Alexander" Morrison and Mary Ann Buchanan prior to 1870 which may require a trip to NC.
Anyway, if you come across anything that may solve these mysteries it would be greatly appreciated and thank you very much for the tip on Sandy's possible correct age.