The Noumerleeën are a miniature image of the entire sandstone region of Little Switzerland. Almost all geologically interesting aspects of the region can be discovered here in a small area. There are many different sedimentation layers and weathering traces. The honeycomb weathering is particularly pronounced, which is reminiscent of honeycombs. In addition to narrow rock passages (lux Schlëff) and half caves, traces of historical use can be admired. On a rocky outcrop there are the well visible remains of the Roman flee-castle Alebuerg and there are numerous traces of former coalfields on which charcoal was produced.
The rocky landscape of the Noumerleeën is part of the northwest layer of the Luxembourg sandstone, which was deposited during the Lias and eroded later. The step slope rises steeply over the hilly country of marl. The marl here is a mixture of clay minerals and dolomite, which originated in the time of Keuper between 210 and 230 million years ago.
The Noumerleeën are crossed by the "Extra Tour A" of the Mullerthal Trail. It can also be reached and hiked through by the following local routes: the 11.1 km long L4 local loop from Larochette, the 3.8 km N2 from Nommern or the N1 from the Nommern swimming pool. At the entrances of the trails there are parkings.