But, are there other Mary Garlingtons in the four Garlington households included in the 1870 Calcasieu LA census and, based on ages and birth states, could they be your Mary J.?
Also, how do you feel about your Mary J's wedding date vs. Hebert (Herbert's) Mary living in his home in 1870? Do you attribute that to faulty 1870 data or something else?
These two questions do not require reference to "The Garlington Family" as the 1870 census data for Calcasieu Parish is on-line via the internet. Have you searched through it for other Mary Garlingtons?