A geocache is a small "cache" which usually contains a logbook and some otherwise worthless trinkets which are then hidden and tagged with a GPS location for other people to find. Basically Geocaching is like a hi-tech version of a treasure hunt or hide-and-seek type game.
I looked for geocaches at Rocky Point at Mosman, St Batholomew's Cemetery in Prospect, Dunrossil Park in Carlingford; and Did Not Find (DNF) any of them. I thought I came tantalisingly close in the cemetery but the container turned out to be full of rubbish.
According to the Geocaching Website this particular geocache is "A deliberately easy cache to show off some local history."
The clue given to help you find GC121H8 at S33°49.689 E151°15.104 is Animals of Lawry Plunkett Reserve
Deliberately easy? I spent possibly four lunchtimes going mad trying to search the bush to find this thing.
Weather permitting, I'm going to finally get around to shooting a series of photos, and I'm definitely going back down there. I think that this is a fascinating and yet rather disappointing piece of history which this particular geocache is designed to show off.