The monitoring of the construction of the motorway in SE Slovenia by karst researchers has also proved to be of great value in the exploration of natural heritage through the deepening of knowledge about the formation and development of this part of the Slovenian karst. Characteristic subsoil karst surface was formed under a cover of sediment of varying depth. Subsoil formation of carbonate rock also marks the entire epi-karst and vadose zone. The surface is carved into subsoil stone forests, the surfaces of the karren are smaller and numerous hollow shafts are filled with fine-grained sediment. The outstanding characteristics of the karst surface are primarily the result of large surfaces of stone forests, which are difficult to detect prior to earthwork or geo-physical research. Most of the surface is above the underground water level. There is only one exception of the motorway section, which was not fully uncovered due to the construction method and because lower road beds were put upon a special grounding. For this reason we could only research the karst formations that had been shaped by water percolation through the karst surface. We did not find the characteristic subsoil karren as those discovered during the earthwork along previous sections, which were also formed by the fluctuation of underground water. Karst features discovered during
construction work give us insight into the characteristics and manner of formation of the karst in the wider area of south-eastern Slovenia; they thus unveil yet another characteristic of karstic natural heritage that was hidden from view, but which also provides guidelines for planning activities on the surface.

stone forest; subsoil formation of carbonate rock; Dolenjska karst; Slovenia