Looking afar toward Guanzi Valley from Baihe or the nearby alluvium, the Zhentou Mountain looking like a pillow is in sight. Due to mining and rainwater washing, there are three large washing marks on the cliff. As they are very clear, some called them three dragons. The entire mountain is formed by limestone. It was originally the lens-shaped limestone in a argillaceous sandstone layer. It is literally called the pillow mountain because of the limestone surrounding the argillaceous sandstone is exposed, looking like a pillow, after the top layer (the extinct layer) was cut away during mining. The limestone here is bioclastic limestone containing fossils of corals and shellfish.