Michael Fitzhubert (Dominic Guard) tries to enter the gap in the monolith where Irma, Marion and Miranda disappeared:
Later in the film Albert (John Jarratt) successfully climbs through the same gap before finding Irma:
This scene was filmed looking down the gap by Irma’s log:
This is also the same gap that Miranda, Marion and Irma disappear into. Peter Weir filmed the girls’ disappearance from the bottom of the gap but Michael and Albert’s scenes were filmed from the top of the gap looking downwards.