It is not unusual to see shells at the beach. It is strange to see the shells that should have appeared on the beach in the Qinghai-Tibet Plateau, and it is still a large piece. There is such a shell in the wilderness of Dulan County in the Qaidam Basin of Qinghai. The locals are called shell beams. shell beam, can only be regarded as a small hill, about 2 kilometers long, 70 meters wide, covered with hundreds of millions of large and small shells. The surface of the shell is covered with a thin layer of saline-alkaline soil. After excavation, it is dig 20 meters down, which is a layer of shells. This is by far the largest paleozoic strata found in my inland basin. These shells, big ones have the size of copper coins, small ones have the size of a thumb, and are mixed with the sediment of the saline-alkali land. Looking at the white ones at a distance, it is still spectacular when approaching. According to geologists, the Qaidam Basin was still a vast ocean, the ancient Tethys Sea. Later, the orogenic movement of the seabed became a plateau, and some speculated that these shells were left at that time. However, local geologists in Qinghai have denied this claim. Their research shows that the formation of the shell beams was about 150,000 years ago. The shape of these shells is no different from the current shells. It is not left in ancient times. . Although there is no definitive study to confirm the source of these shells, the geological changes in the sacred fields are an indisputable fact, and here it must have been a place where water and grass are abundant.