1-1What is the bedrock of the cave made of ?

The rock of the cave is sandstone. It took millions of years for sand in the sea and tideland sand to harden into rock. The present geography has been formed by the rise of the ground and erosion of the bedrock by river flow. Observe the bedrock closely, and you will see diagonal lines. These lines are a record of the natural phenomena that happened in ancient times when the sea sand deposited was piled up aslant.