At the posted coordinates look to the east and find Richardson.
You will then be able to figure the final coordinates.
N 40 57.ABC W 96 08.DEF
A = The last digit of the year Bertha died, then substract 4
B = The last digit of the year of Floyd's birth
C = The third digit of the year Bertha was born
D = Count the letter's in Bertha name, then divide by two
E = Count the letter's in Floyd's name, then subtract two
F = The first digit of the year Bertha was born
Note: the container in the stump is not the cache; it is a letterbox