You must first travel to a small predestrian foot bridge located at the given (above) coordinates. Once there, count the number of turtles in the little park to your E. Number of turtles = X. Then count the number of boards in the boardwalk of the bridge. YYY = 254 - # of boards.
The Cache (a blackened tupperware container) is located at N 42 deg 1X.759' W 84 deg 26.YYY'.
I placed the standard stuff in the cache, a logbook, camera (take your pic!), etc. Also included are a Ferrari, coins from Haiti, a lizard bookmark, an antler, and a (guaranteed never to have had chemicals in it) 500 mL Erlenmeyer flask.