The exposed terranes between Meishan and Yako belongs to the terranes of the Central Backbone Range. They mainly consist of metamorphic sand stone, argillite, slate and phyllite that had gone through metamorphosis and layers of lens-shaped limestone mass and igneous rock mass. Basing on their geological characteristics, the terranes along the study area can be divided into three geological units (from bottom to top): the Bilushan terrane, Liguan terrane, and Meishan terrane. The geological development in the study area is influenced by complicated underlying geological factors such as terrane and geological structure. Sites that have endured severe erosion and weathering show unique topographic features of mountains and rivers. The topography of the stretch between Meishan and Yako along the Southern Cross-Island Highway can be divided into three categories: slopes, mountaintops, and highland lakes. The Laonong River is the main river in the area, and the Weijin River and Lakuyin River are two most important tributaries of it. Together, the three rivers and a large number of small tributaries form a distinctive geological landscape along the Southern Cross-Island Highway.