The variegated Medves Area (160 km2) lies between the Zagyva, the Tarján-patak and the Bárnai-patak rivers and the Hungarian-Slovak boundary in North Hungary. Due to its natural values a considerable part of the area has been declared to be protected, it is known as Karancs-Medves Landscape Protection Area.
As regards the geology of the area, particularly the typical sequences of the Tertiary era can be studied. Some facies pattern of the stratigraphical formations of sedimentary rocks should be very suitable for pointing out key sections. In various places the special forms of the outcrops of these rocktypes mean landscape-constituent role and have great geomorphologic importance. The "horst-graben-type" geological structure promotes the occurrence of these forms, parallel and perpendicular faults cut the landscape unit, therefore it can be characterised by steeply emerging horst-like hills (e.g. steep sandstone walls with the loaf-like concretions bulging out) and between them narrow trenches and deeply dissected erosional valleys.
In spite of the domination of the sedimentary rocks great part of the area is covered by volcanic rocks. Among them outcrop of Miocene rhyolitic tuff near the village Kazár has great geomorphologic importance forming the only badlands-like landscape of Hungary. The Pliocene basaltic rocks have either stratovolcanic structure or consist of only lavas, forming lavaplateaus, small cones, dykes or necks. Most of these outcrops rise slightly above its surroundings, but there are some basaltic beds with considerable extension, often forming conical shape with steep slopes. Occurance of basaltic columns are also frequent. Some of these outcrops can be seen due to the mining activity, mainly in abandoned mines. At the foot of the hills block fields created mainly by periglacial attrition can often be found.
The anthropogeneous forms are very frequent in the Medves Area, where the change of the natural environment caused by human activity is beyond average degree. Especially the landscape forming effects of the mining of the basalt and the browncoal and that of the related industry and infrastructure changed the surface. Enormous mine dumps, inclined shafts, bogie-tracks, transmission lines, narrow-gauge railway tracks, ropeways, cuts, ramparts, tunnels altered significantly the surface. By now almost all of the mines has been closed, but many of the underground galleries collapsed and therefore depressions occurred on the surface. The biggest change caused by undermining can be seen on the stratovolcanic beds of the Szilvás-kő, where trench-like deep fissures came into being.