The first geological relic spot in the route can be found on the mountains in northeast of the square, and is called as "Feilaifeng" by local people with its altitude of 1,263 m. The mountains consist of longer microcline migmatitic granite of black cloud with grey and yellow grey colors in the middle Vatican period. They are structured with medium grains and they are featured with metasomaric texture, clump-shaped and slightly gneissic structure. They mainly include oligoclase (39%), microcline (23%), quartz (30%) and biotite (7～6%). From the recent measurement, the geological age of 173 Ma existed in the phase belt. Hundreds of holes were developed on the approximately northwest- southeast granite wall. Hole monomers are with different sizes and irregular shapes. They often have an elliptic form with a height range of 1-2 m and a depth range of 0.3-1 m. They cover a distribution area of about 600 m2 and are mainly distributed on two horizontal planes. As for hole forming reasons, some scholars think that parts of granite contained inclusion of metamorphic rocks, and so holes were generated by differential weathering and stripping in a long term, while some other scholars hold the opinion that the kind of holes was a typical wind-eroded habitacle, and was also called as stone nest. Volume of Minerals inside rocks expanded to different degrees due to heated palisades basked by the sun, and thus the differential weathering by heating power was generated. In addition, when rocks were heated, saline solution inside rocks rose along the capillary to pores near the surface in order to crystallize. The crystallized saline solution swelled rocks and makes rocks disintegrate. As wind eroded and weathered the loosen rock surface, many shallow and small pits formed. Then sand blown by the wind entered and eroded pits, and thus pits continued to deepen and expand. Pits gradually developed into current holes.
