The Adamson Estate is part of my short list of favourite places in all of this city. Please take the time to check out this park while you are here.
The cache is not at the posted co-ordinates, but is a bonus cache for the Adventure Lab Scooby's Case File #905: Haunted Mississauga. The final co-ordinates for this cache will be revealed when you solve the mystery.
Update: It seems Zeph made short work of that cache. Seeing it was a Scooby Snack, he ran off with the container almost immediately, and apparently erected a sign to keep us out. New cache location and container that hopefully is now ghost proof!
I hope you take the time to explore the locations this Adventure Lab will take you to, as you will see some of the nicest places the City of Mississauga has to offer.