Jim,
 
Not elementary at all but sometimes frustrating!
We would agree with Jim & Mike that the footstones
were originally placed with the initials facing away
from the headstone.
 
However, big caveat here... footstones were (are)
easily removed by people, animals, erosion etc.
It has been our experience that they are often
replaced improperly by family, visitors, cemetery
employees. Also if there is no headstone, the
footstone may be placed on another grave or a
vacant spot on the ground with no grave association
at all. Cause of much futile dirt removal :--)
 
As Milk Polk says, you will ultimately have to go
with the archaeological clues on the ground. Also
the cemetery plat (plot) map if there is one...
 
Best,
 
Gene Prince
Crabtree, Prince & Assoc.
Historic Cemetery Studies