1. The local people in the hometown of keel collectively refer to all kinds of animal fossils as "keel" and the tooth fossils of animals as "dragon teeth". "Dragon's bone" and "Dragon's tooth" are not excavated as ancient cultural relics, but as an important Chinese herbal medicine, which has a special hemostatic effect.

1 100 million years ago, Qingyang area was a water network area intertwined with rivers and lakes. There are both sediment deposition and the growth of aquatic animals and plants in rivers. After these things were buried, under the high temperature and high pressure of millions of years underground, sediments became rocks, animal bones became fossils, and organic matter became oil or coal. Inferring the climate, landforms and other environments at that time from geological signs such as strata and fossils, which is what geologists often say. 1978, a complete paleontological fossil was found on the river bank. The fossil is located in the gray-white sandstone stratum of the Late Jurassic and was deposited about 1 100 million years ago. The ancient animal fossil found is a dinosaur named "pterosaur around the river". The discovery of fossils proves that there are abundant aquatic plants here and the climate is mild, which is suitable for animal reproduction.

In the later geological evolution process, the water area gradually decreased. By the tertiary period 20 million years ago, it had become a swamp, where many kinds of land animals lived. A set of red soil layers was deposited. There are a large number of animal fossils such as three-toed horses and rhinoceros in the red soil exposed today.

The subsequent geological period was Quaternary (2.48 million years ago). The early Quaternary is called Pleistocene and the late Quaternary is called Holocene. During the Pleistocene, a set of loess layers with a thickness of more than 200 meters was deposited in the vast area of North China. Qingyang is the best preserved area of loess deposition, with a complete loess deposition profile. The Pleistocene loess is divided into three layers from bottom to top, the lowest layer is called Wucheng loess, the upper layer is Lishi loess, and the top layer is Malan loess (also known as Salawusu Formation). Wucheng loess is the oldest, with more than one million years. Malan Loess (Salawusu Formation) is the youngest, ranging in age from tens of thousands to hundreds of thousands of years. Abundant animal fossils have been found in many places in the strata of Salawusu Formation, with tons of fossils unearthed every year, including more than ten species such as the image of rhombus, bighorn deer, hairy rhinoceros, primitive cattle, wildebeest, wild horse and zokor.

2. When the loess of Salawusu Formation was deposited in Pleistocene, this area was still a region with abundant rivers, lush vegetation and beautiful scenery, which was suitable for animals to thrive, which is not comparable to today's arid environment. Many remains of early human activities have been found in Huangshi area of Salawusu Formation. 1920, three paleolithic artifacts were unearthed in Qingyang area, which is also the first paleolithic unearthed in China. It was identified as a rough tool made by human beings as early as 200 thousand years ago. It proves that there were human activities here as early as 200,000 years ago, which means that people at that time had lived in this land with wild horses, dogs and zokor. The Pleistocene (including the Salawusu Formation) corresponds to the Paleolithic Age of human society. The typical Paleolithic site is Giant Home Site, which is about 30,000 years ago. There are many stone tools, accompanied by more than ten kinds of mammalian fossils, and the site is buried in a gray-green silt layer.

The Neolithic Age began about 654.38 billion +0 billion years ago, which is equivalent to the geological Holocene. Neolithic remains were found in many places in Qingyang area. There are a large number of pottery fragments such as painted pottery (bowls, cans), red pottery (cans, bottles) and gray pottery in Neolithic sites. Typical Neolithic sites such as Nanzuo Village in Houguanzhai (all belong to Yangshao culture).

Then came the Xia and Shang Dynasties in ancient China, and its cultural remains were also found in many places in Qingyang. 1979 A white jade elder brother of Shang Dynasty, 38.6 cm long and engraved with the words "Zhaciwu", is a national treasure cultural relic. Then there are a lot of relics of the old country of Zhou Zu.

3. Archaeological Discovery of Yuan When tracing back to ancient sites, we should pay attention to an archaeological discovery made by Comrade Yuan. At present, it is known that pottery began to appear in the Neolithic Age, and the oldest surviving pottery fragments are no more than 1 10,000 years ago. 1992 Yuan Xiaoqi, a geologist of Changqing Research Institute, found more fragments of ancient pottery when he was conducting geological survey near Qingyang. Pottery chips are located in the stratum of Salawusu Formation, which contains paleolithic, carbon chips, ashes and animal fossils. The carbon 14 of this stratum has a history of 25,000 years. This discovery has advanced the history of human pottery making by more than 1 10,000 years, which is an amazing discovery.

At present, the only uncertain factor is whether the stratum found in the pottery is the original undisturbed stratum or the stratum that has suffered secondary collapse. If it belongs to the subsidence stratum, it will inevitably be mixed with some later pottery pieces, because the riverbed terrace often has the collapse of the original loess layer. If this possibility is ruled out, then Yuan's discovery will make a major revision to the history of human civilization, which is of great significance.