A southern outlier, which is also part of the Peterskopf massif, is the 300-metre-high Kästenberg (Pal. for Kastanienberg or chestnut hill), is host to the remains of the Heidenmauer, a large Celtic settlement with a 2.5 km long circular wall, which was built around 500 B. C., as well as the Roman quarry, the Kriemhildenstuhl, which was used until the 4th century A. D.