Introduction to Mashan: Jimo Mashan, also known as "Ma'an Mountain", the main peak is 211 meters above sea level. The mountain is mainly made of andesite porphyry, which is gray-green and gray-brown. It is a high-quality building carving stone. There are square columnar joints in the southwest of the mountain. The cross-section of a single tree is about 1 meter and the height is about 30 meters. They are compactly arranged, straight and straight, just like a dense forest, which is spectacular, hence the name "Mashan Stone Forest". In terms of its geological value, its scale is larger than the Liutai Stone Pillar in Nanjing, and is comparable to the basalt columnar jointed basalt body of the "Devil's Tower" in the United States.