Finding this bonus cache should be a fairly easy task once you have completed the nearby Terra Nova Adventure Lab. Check your journal entries for each stage to find the numbers you need to plug into the following matrix:
N 49 10.(A/2)DA W 123 11.(E-D)EA
Please remember to stay on the trails whenever possible and try to leave the cache site in the same condition it was when you found it. This is a log-only cache with no room for swag or trackables, and there is no pencil inside so please bring your own writing implement.