This side valley of the Oker is largely unknown. At the top corner of the Okerstausees, the Kellwasser below Altenau flows east into the reservoir.

This valley has a name in the sciences of geology and paleontology worldwide. As early as 1850, the geologist and botanist Friedrich Adolf Roemer recognized a geological survey in the Kellwassertal, which led him to carry out more detailed investigations. Roemer made an important contribution to geological and paleontological research with his research and descriptions in this regard.

Today, about 160 years later, we have the following state of knowledge:
In the earth’s antiquity or scientifically paleozoic, the life of the multicellular began to develop primarily. In the period from 542 – 251 million years ago today, life in the oceans first developed. Later, the land fauna and flora began to develop. But this development did not go smoothly. In this age, the five large, known mass extinctions took place. The reasons for these so-called mass extinction events are not yet known, but the first and second reasons are impacts of celestial bodies, as well as enormous volcanic activity. The most famous of these extinction events is the Cretaceous KT event, which led to the spectacular extinction of the dinosaurs and is attributed to a massive asteroid impact.

For the Harz region of a certain importance is the “Kellwasser-Event”. Not because this extinction event, which took place in the Upper Dovon (395-385 million years before today), would have affected only the Harz, no, it affected the whole earth like all five events, but because it has its name from here. After this location in the Okertal, the dark, mostly mergeable rocks are called Kellwasser-Kalk and the event as a Kellwasser event. Among the five major mass extinctions, this event was the third-worst in the number of extinct species.

The Kellwassertal thus has a worldwide standing for the sciences that deal with the geological and paleontological origins of the earth. In order to keep these layers clearly visible, the digestion was exposed on a large scale some time ago. Representatives of the German Society for Geosciences, the State Office for Mining, Energy and Geology, the Geozentrum Hannover and the Senckenberg Institute were involved. In addition, an information board funded by the Harz Regional Association provides information on the geological characteristics. A new geopoint has thus been created in the Geopark Harz, which represents a real upgrade of the entire geopark.