Why is Yushan Town in Lantian County, Xi City, Shaanxi Province called "Yushan Town"?

Yushan Town is located 20 kilometers east of Lantian County, at the northern foot of Gongwangling, a world-famous Lantian ape-man site, at the intersection of Zhong Nanshan extension and Lishan fault, surrounded by spiritual practice in the north and mountains in the southeast. (Yushan County was once located here in the Northern Zhou Dynasty, and the town has a history of 2,000 years. According to legend, there is a jade bridge in Yushan Village of this town. During the Xianfeng period of the Qing Dynasty, jade was sent to the court, and Empress Dowager Cixi carved a jade seal for herself, hence the name Yushan.