Delago Hole

The Delago cave is a cave located in the Pilis Mountains within the Danube–Ipoly National Park, situated in Oszoly, and is featured in tourist guidebooks. Its impressive entrance is clearly visible from a distance.

Description

It lies in the outskirts of Csobánka, on the Margit ridge. In one of the rock walls of Oszoly, on the Delago rock wall, there is an impressive, spacious, oval, west‑facing, naturally formed entrance that is clearly visible from afar. In Upper Triassic white‑filled thick‑bedded Dachstein limestone, probably due to thermal water action, a five‑metre‑long rock cavity was formed, which has no sedimentary filling. Calcite occurs in the cracks of the limestone. The dry cave narrows upward into a small dome, in which a predatory bird sometimes appears. The entrance can be reached by easy rock climbing.

In 1981 the cave was first called Delago‑odú in the literature. In the literature the cave also appears under the names Delago‑odu (Kordos 1975), Delago odu (Kordos 1971) and Delagó‑odú (Kraus 1997).

Research history

In the book *Pilisszék* (Piliss Guide) published in 1967 it was mentioned that, on the southern side facing Oszoly Csobánka, among the forest‑surrounded limestone rocks, several insignificant cavities are present. According to the report published in the 1969 Karst and Cave Research Bulletin, in August 1969 the Speleology Cave Research Group placed fixed points in Oszoly and in eight smaller or larger cavities on the Oszoly side during a camp organized in Kevélyek. In that year László Kordos prepared a colour slide on which the cave is visible. On 26 April 1970 László Kordos performed climatological measurements on the surface and in the cave with an Assmann aspiration psychrometer.

In 1970 László Kordos and Erzsébet Wehovszky surveyed with lost points, a mining compass and in that year, based on the survey, László Kordos drew and compiled the floor plan map and the longitudinal section map, which were made at a scale of 1:100. According to the survey the cavity is 2.5 metres long and 5 metres deep. The Speleology Cave Exploration Group's 1970 report contains a detailed description of the cave. The report reads that the Delago cavity widens upward, narrowing into a small dome. The rock cavity is regularly used by a large predatory bird, as evidenced by feathers, droppings and small breastbone fragments. The cave can be viewed with a short rock climb, without equipment. It is not located on the frequently used climbing routes and is relatively rarely seen up close. The 1970 maps were included as an annex to the report.

In the book Pilis Travel Guide published in 1974, in the list of caves of the Pilis Mountains and the Visegrád Mountains (pages 19–20) it is mentioned that among the caves of the Pilis Mountains and the Visegrád Mountains are the Oszoly caves. According to the section describing the caves of the Pilis Mountains, there are about a dozen small caves among the Oszoly rocks rising above Csobánka. These were mapped and regularly explored by the Speleology Cave Exploration Group. Most of these small caves are not very spectacular, but they must be mentioned because some of them, located in the Oszoly rock walls regularly visited by tourists, especially climbers, and near them, provide excellent bivouac possibilities. The Oszoly collapse can be entered through an oval opening visible from a distance under the rock wall named Delago, leading upward into a 5 m cavity.

Published in the 1975 MKBT Report was the 1970 report section concerning the cave together with the maps included in the report. The study showed, among other things, that its length is 5 m, its depth is 5 m and its horizontal extent is 2.5 m. Sometimes rock climbers visit it. The publication contains a site drawing on which the geographic locations of the Csúcs Hill and the Oszoly caves can be seen. The drawing shows the geographic location of Delago-odu.

In the manuscript written by Bertalan Károly and completed in 1976 it is stated that the Delago odu is located in the Pilis Mountains, in the Kevély group, at Pomáz. The Oszoly collapse opens under the wall of Delago into an oval‑shaped cavity. Its entrance, visible from a distance, can be approached by a short rock‑climbing climb. The upward‑widening cavity is 2.5 m long and 5 m deep, narrowing into a small dome. The cave part of the manuscript was written based on two literary works.

In the 1981 first–second semester issue of Karst and Cave it was made public that the cave number of Delago-odu is 4820/19. In the book *Caves of Hungary* published in 1984, which lists caves nationwide, the cave appears among the Pilis Mountains caves under the name Delago-odu. Associated with the list is a 1 : 500 000 scale map showing the geographic location of the Dunazug Mountains caves, on which the geographic location of the cave can be seen. In 1990 József Kárpát drew an overview map on which the geographic locations of the Oszoly rock‑climbing school caves can be observed. This map shows the geographic location of Delago-odu. The guidebook published in 1991 repeats the cave description from the 1974 guidebook and the general description of the Oszoly caves.

It is not included in the 1991 compilation written by József Kárpát. In the 1996 cave day tour guidebook the cave description from the 1991 guidebook and the general description of the Oszoly caves are repeated. On June 6, 1997, based on József Kárpát’s 1990 Oszoly overview map, Sándor Kraus drew a site plan showing the geographic location of the caves in the D part of the Oszoly rock groups. The geographic position of the Delagó-hole can be seen on the drawing. In Sándor Kraus’s 1997 report it is readable that the Delagó-hole already had a map before 1997. The 1997 site plan was included in the report. The book Hungarian Mountain Sports and Tourist Encyclopedia published in 2005 mentions that in the Oszoly forest rock blocks and small cave openings alternate scatteredly.