The cache is not at the posted coordinates, but you will need to go there to collect some information. You will see some letters carved into a prominent beacon. Call the first letter A, the second B, etc.
The cache is at n41 26.(D)(E)(A+B) w090 50.(E-B)(A)(C-F)
You can validate your puzzle solution with
certitude.
As I was placing the final cache, I heard some ominous creaking and bubbling noises coming from the river. Now, you may say it was just the ice cracking, but......what would Fox Mulder say? [CUE THE THEME MUSIC!]
Have fun and don't slide down the hill at GZ like I did.