The 2 photographs here are Soft Tree Ferns, Dicksonia antarctica. They have fallen or bent into an arch. On reaching the ground, the stems turn vertical and continue to grow and hence having the appearance of giant caterpillars crawling on the forest floor.
But in Dicksonia Forest Ravine, there is a forest of Dicksonia antarcticas, and many of them are in this caterpillar state. More photosgraphs of these caterpillars, and a trip report to the ravine are in my blog:
By the way, the ravine is like an enchanted world, like a mythical fairy land. You should visit it if you have a chance.
(Dicksonia Forest Ravine is in the north-western corner of Blue Mountains National Park, NSW, Australia. Click on the above blog link for the precise location.)