The region of Guilin takes on a Karst feature. Geological studies show that the original Guilin was a vast expanse of sea until 300 million years ago, the crustal movement made the limestone deposit in the deep sea rise and gradually formed to land. Being effloresced and eroded, it finally became the mountains with different shapes, the grottoes with beautiful views and the aboveground rivers with mysterious stories. These mountains with strangely shaped peaks and caves of unique formation, together with the crystal-clear Lijiang River that surrounds the city, characterize Guilin's scenery and have brought it world fame. The main mineral deposits of Guilin are iron, aluminum, zinc, barite, talcum, and limestone.