At the posted cords you will find a Benchmark with a date stamped in it.
A temporary four digit number is on the fence just east of the bench mark.
For the North cords take that number and subtract 1523.
For the West cords take that number and subtract 1728.
Don't forget to log the Benchmark. Click on "all nearby Benchmarks".
If you don't sign the final don't log this multi cache.