Picnic at Hanging Rock is a masterpiece of psychological fiction in which we see an awful thing happen from a great distance and are only given enough clues to guess at what happened to the missing girls. Excellent cinematography and a musical score perfectly chosen both of which become Weir trademarks first appear in this film. They are clearly missing in the Cars that Ate Paris his first full length film. Though many people have offered suggestions both realistic and absurd as to what happened to the ladies, everything but Dingo attacks have been suggested, we are kept in the dark on purpose. The novel that the film was based on suggested, almost as an afterthought, that the story might be true. This claim was as much a fiction as the rest of the novel.
The site, Hanging Rock, is identified with a mythic highway man and all the things we observe happening have elements of the supernatural. The people as in many Weir films communicate the most critical ideas with out talking. A significant plot development in this film, we hear thoughts..see people moving on ward as if drawn towards their doom, but Weir never bothers us with needless Dialog..how much weaker would the plot be if we heard Miranda calling to her companions "follow me, we must reach the top." It is also critical to the developing sense of spirituality and intuitive communication we see in Gallipoli and Witness.
Finally, if we knew what happened to the girls, any speculation about the fate of those at the school would be moot. The mystery explains the accusations by the girls, parents and staff and the eventual downfall of most who worked there.
Those who do not like the film fail to see it as an Aussie Gothic film as innovative in its day as Wuthering Heights was in its.