• The basalt layers in the north and northeast are interbedded with sandstone and shale, which is a standard topographic landscape of Yuwengdao.
• There is a silica sand layer on the north shore, which is made up of exotic rocks. This silica sand layer has good water permeability, plants are not easy to grow, and its surface is degeneration, so it forms a badland.

Xiaomenyu stratum contains iron silica sand and outcrops of mud layer and coquina. The west side of Xiyu Social Welfare Building is the most obvious. Therefore, this layer is called the Xiaomenyu layer.

After years of erosion, it has now become a sea-eroded arch.

• There is a great outcrop in front of the Whale Cave for observing the condition of basalt lave flow covered on the sedimentary rock. In the meantime, it can be found that the plants covered by the lava eruption form a layer of carbide, and some trace fossil are still preserved.
• There are two sea stacks towards the east
• There is a row of thick weathering columnar basalt wall on the opposite side. Beneath that, there is a layer of black material about 1 foot thick. It is formed by plant carbonization covered by lava eruption. Trace fossils can be found nearby.
• The basalt joints at or near the Whale Cave are affected by rainwater etch and weathering; beautiful weathering lines can often be found at the junction of joints.

There are unique “beehive farmlands” near the gullied land. The stone walls of these beehive farmlands are built to withstand the strong northeastern monsoon, so these farmlands are windproof to grow through the winter.

1.Motorcycle/Car: From Magong City, take county highway 203, turn left at Dongwei, pass Baisha Township, cross the Penghu Great Bridge, turn right at about 26km of county highway 203, continue to pick up the Penghu local road 2 to arrive the destination.
2. Bus information: Take Waian Line passing Xiaomenyu to get to Xiaomenyu Station. Timetable - Blue line - Waian Line
3. Taiwan-The Heart of Asia: Timetable-Magong Shuttle Bus North Ring Line

1. Be careful when climbing up the Whale Cave.
2. Big waves during the winter northeast monsoon, so it is recommended not to stay too close to the coast to avoid danger.