Mt. Wilkołak (367 m) is a striking basalt hill in the northern part of the Kaczawskie Foothills, about 100 m high. It is one of the symbols of the Land of Extinct Volcanoes, widely known for its well-developed columnar (thermal) jointing arising from lava cooling. The age of basalt was determined for 20 million years (+/- 1 million), which means Early Miocene. However, the complicated pattern of columns indicates that volcanic activity in this place was surely multiphase. In the present-day appearance, Mt. Wilkołak is a neck, that is an old volcanic conduit built of lava that solidified on the way to reach the long eroded volcanic cone.
The shape of the hill was considerably altered by rock quarrying. An old quarry was located on the west side of the peak and operated in the 19th/20th century. In 1959 a small nature reserve “Wilcza Góra” (Wolf Hill) was established, covering a mere 1.69 ha, aimed at the protection of geological outcrop. The height of the quarry walls approaches 30 m. They reveal variously oriented columnar jointing and pyroclastic deposits, which also contain pieces of sandstone detached from the sides of a former vent. The eastern part of the hill is off limits because of the operating quarry. This is unfortunate since the complete cross-section of a volcanic conduit is exposed within it. Features of interest are large sections of columns standing upright, concentric pattern of joints known as the ‘basaltic rose’ and basalt veins discordantly cutting through the Cretaceous sandstone.