The cache you are looking for is an Eclipse Mint tin.
Here is the sight of the McLachlan school. From 1929-44 this was a one teacher, small rural school, where all of the students (and the teacher) travelled from miles around by either bycycle, horseback or foot, to attend. The view out of the window would have been a daydreaming students delight, being able to see for vast distances in almost all directions.
Landmarks that can be seen from here include... Darke Peak range and Caralue Bluff to the north east, Mt Wudinna to the north, Ucontitche Hill to the north west, Mt. Wedge to the west and the hills of Sheringa to the south west. Less than a kilometre almost due east of this point, you can obseve a trigg point. Thismarker signifies the highest point in the whole Lock district.