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
Geology of the Grand Canyon area Limestone averages 505 million years old and is made of gray, thin-bedded limestone that was deposited farther offshore from calcium carbonate precipitates (see 3c in figure 1). The western part of the canyon has a much thicker sequence of Muav than the eastern part. The Muav is a cliff-former, thick. These three formations were laid down over a period of 30 million years from early-to-middle Cambrian time. Trilobites followed by brachiopods are the most commonly reported fossils in this group but well-preserved fossils are relatively rare. We know that the shoreline was transgressing (advancing onto land) because finer grade material