Rawhiti Cave become increasingly finer deeper down into the cave. A short walking track leads halfway down into the cavernous opening to a viewing platform. The diverse twilight-zone flora near the entrance of Rawhiti Cave makes this cave nationally significant. Over long periods of time, plant growth on the cave formations causes them to grow towards the sunlight as more calcium carbonate is deposited regularly on top of the plant growth. This phenomenon, called phytokarst, is most evident on the larger stalactites near the cave entrance, which are strongly curved outwards due to the heavy moss and fern growth on their sunlit
Cave of the Mounds National Park Service designated the cave as a National Natural Landmark. The limestone from which the cave was carved began forming approximately 488 million years ago, during the Ordovician Period. During this time, much of North America was covered with warm, shallow seas. Over millions of years, calcium carbonate shells from tiny marine organisms accumulated on the sea floor, forming enormous quantities of limestone. The type of limestone in which the cave was formed is called galena dolomite because of its high concentration of the lead ore galena. The cave began forming about a million to a million and a