Has anyone noticed... (possible spoilers)
Michael was having tremendous difficulty reaching the crevice, but in a longer shot he wasn't climbing up steep rock, he was crawling on level ground, as if some force was holding him back.
Michael and Irma had the exact same bruised cuts on their foreheads, in the same place, position, shape and length.
When they first arrived at Hanging Rock, when Miranda opened the gate, there was a brief rack-focus shot of the notice board. They were too faded to read, but there were two sheets of paper of the same size and in the same positions as the "Missing: Presumed Dead" posts towards the end of the movie.