In May 1947, during the process of oil exploration in Haishi Bay, the famous geologist Sun Janchu collected a few pieces of skull fossils and dinosaur fossils on the Ma households on North Mountain. These fossils were transported to China Geological Survey of Vertebrate Paleontology Laboratory in Nanjing, shocked all the Chinese scholars in the ancient animals’ circle. From 1947 to 1956, geologists and scientists of vertebrate paleontology went to Haishi Bay to dig out ??dinosaur fossils for four times. In May 1965, under Yang Zhongjian, dean of vertebrate palaeontology in China’s auspices, the dinosaur fossil unearthed in Haishi Bay and the later found in another unearthed in Hechuan, Sichuan 10 years after the first fossil were recovered in frame, and named "Hechuan, Mamenxi Dinosaurs." The unearthed dinosaur fossil in Haishi Bay which has 22 meters-long legs has been exhibited in the Museum of Ancient Chinese animals. The other a Sichuan Mamenxi dinosaur was recovered and shipped back to be placed in Chengdu Geology in Sichuan.

The name of "Mamenxi dinosaur” was originated in the fossil of the sauropod, long-necked, and herbivorous dinosaur discovered in Mamenxi in Yibin, Sichuan.

In 2000, Hualong Square was built in Honggu, and a sculpture of Mamenxi dinosaur was built in the square, with a length of 20 meters and height of 12 meters, made in accordance with reproduction picture, with majestic beauty and became the landmark of Honggu District.