There is a lot of gnessis rock in the black forest...........the storytellers..........the Brothers Grimm were from Bavaria...................also.........to note.........they did a lot of research from more Northern Europe myths........Norse myths they read about in German libraries..........of Ireland to Norway to Sweden.............

Bavarian Forest - Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Bavarian_Forest

Wikipedia

Geographically the Bavarian Forest and Bohemian Forest are sections of the same ...and Black Regen and leaves the mountains towards the city of Regensburg. ... The Pfahl, a 150 km long rock formation; Teufelstisch ("Devil's Table") near  ...