[2] The cave was formed in poorly consolidated Tertiary limestone laid down in a shallow sea in the Oligocene and early Miocene geological epochs, between about 35 and 15 million years ago.[5] With the assistance of a retired gold miner from Western Australia, Charles Hirth, they excavated fissures in the soft rock to link the caverns together, and drove a 45-degree shaft provide better public access.[5][6] Meanwhile in 1939, Bunny’s daughter Nancy Hutchesson, wrote to Buckingham Palace seeking permission to name the cave after Princess Margaret Rose, the future Queen Elizabeth’s younger sister.[7] Improvements included reconstructing the old access road, a new residence for the warden, camping ground upgrades, toilet blocks and picnic facilities, a new visitor centre as well as a more reliable 240V mains power supply.The focus was attracting family groups with a low entry fee of 30c for adults, and 10c for children[2] In 1973, the Land Conservation Council recommended the Princess Margaret Rose Cave be added to the enlarged Lower Glenelg National Park, but it took until 1 December 1980 for a handover to take place.
Mr Jack "Bunny" Hutchesson in the Princess Margaret Rose Caves in 1961.