Háromlyukú Pothole

The Three‑Hole Pothole is among the specially protected caves of Hungary. It is located in the Pilis Mountains in the Danube–Ipoly National Park. It is also presented in tourist guidebooks.

Description

The pothole is on the edge of Csobánka, on the southern slope of Hosszú‑hegy, to the south‑east from the ridge. It opens three entrances in a karst‑bush area. It can be reached from Csobánka via the tourist trail marked with a green stripe.

Vertical cave, a typical collapsed pothole. It formed in Upper Triassic Dachstein limestone. The northernmost entrance is of the best condition, the next one developed in much more friable rock. Each entrance opens into a vertical shaft. On the wall of the shaft tube‑shaped dissolution traces can be observed. From the bottom of the shaft the Bear branch starts, which was named based on the bone remains found here. According to its form and mineral deposits the primary cavity is of hydrothermal origin. The cave with a sealed entrance can be visited only with permission and the use of rope‑technical equipment.

In the literature the cave occurs under the names Three‑Hole cave (Gazdag 1990), Hosszú‑hegy cave (Bertalan, Schőnviszky 1973–1974), Hosszúhegy cave (Kadić 1952), Hosszúhegy Three‑Hole cave (Schőnviszky 1964), Hosszúhegy pothole (MKBT Invitation 1976), Hosszú‑hegy I. cave (Kordos 1984), Hosszú‑hegy II. cave (Kordos 1984), Hosszú‑hegy cave (Kordos 1984), Hosszúhegy cave (Schőnviszky 1937), Hosszúhegy Three‑Hole pothole (Tamasi 1998), Hosszúhegy Three‑Hole cave (Takácsné 1990), Hosszúhegy pothole (Bertalan 1976) and Hosszúhegy pothole (Jakucs, Kessler 1962). In 1967 the cave was first called Three‑Hole pothole in the literature. It received the three‑hole name because it has three entrances.

Research history

In June 1875 Karl Wissinger learned that there was an as yet unexplored cave in the Pilis, located on the estate of Mr. Litvay, near Pilisszántó, northeast of the settlement, almost in the middle of Hosszú‑hegy. The hole was vertical and therefore no one dared to enter it. Karl Wissinger visited it accompanied by Mr. Eisdorfer. Its three‑meter‑long and one‑meter‑wide entrance was covered with tree branches so that passing sheep and other animals would not fall in. The branches were removed and an approximately vertical shaft became visible. Stones were thrown into the shaft and the rolling of the stone soon stopped. From this they concluded that after the shaft there was a shallow slope on which the thrown stone could have stopped. Equipped with the tools necessary to examine the cave, Karl Wissinger attached his rope to a tree, descended 22 meters deep and stopped.

Eisdorfer has descended and a few minutes later the two of them were standing on the large limestone rocks coated with clay, which were the foundations of the slope. Since the natural shaft turns to the west, the sunlight could only be seen slightly. At the bottom of the shaft there is a chamber in which many snow‑white stalactites and many slightly yellowish stalactites occur, some of which reach a length of 50 centimetres. Among these, the very interesting paper‑thin walled, 15 centimetre long stalactite tubes, which are filled with water and therefore show the formation of the deposits well, are notable. There are also flowstones and in several places where horizontal fissures have opened, they have merged and form columns 25 centimetres high. From this approximately six‑metre‑high chamber three passages widen in three directions, of which the longest one slopes gently downwards to the northwest and is about five metres long. At about the 5th metre it narrows and ends.

Southwest there is a four‑metre‑long side branch that rises upward, which also becomes impassably narrow. The third branch, to the north, can be considered the protrusion of the chamber. Its first description, floor plan map and longitudinal section map appeared in the *Földtani Közlöny* in 1875. According to the study it belongs to the odvas caves group and was formed in Dachstein limestone. The cave is at 11 °C, a temperature that is probably constant, because during a two‑hour stay inside the temperature did not change. Apart from the stalactites and occasional falling water drops, the cave is dry, which implies that there are many cracks in the cave floor through which rainwater can drain. Because of the shape of the cave it was not expected that there would be ancient animal bones inside, a finding that was proven after a long search. At the end of the southwestern side branch Karl Wissinger found the skull of a young fox and several vertebrae and some limb bones. The fox probably fell into the cave by accident and could not get out. Because of the discovery there is one more Pilis cave.

Ferenc Schafarzik mentioned in the 1884 Geological Gazette that Karl Wissinger presented the cave discovered on Long Hill near Pilisszántó in the 1875 Geological Gazette. In the book *Budapest környéke* which appeared in 1900, the cave is described based on the information from Karl Wissinger’s paper. In the summary written by László Schőnviszky and published in the 1937 volume of *Turisták Lapja* it is stated that the Long Hill cave is at the border of Pilisszántó. According to Karl Wissinger’s description, a 22 m deep sinkhole entrance led to a small chamber, from which two other small side passages opened. Many stalactite formations were observed in the cave. According to the old description, the cave has not yet been found. Published in the 1948 Hydrological Gazette, it was reported that with the prominence of Long Hill the karst water level descended in Long Hill and the spring series of the Ziribári, Long Hill, Pilisszántó and Szurdokvölgy caves ceased to operate.