Realengo I

Of the 5 possible known entrances in the system, the main entrance or sink is the most important. This one, 1x2, leads to a meander of comfortable dimensions which, after receiving an inflow on its left side, reaches a 3.5 metre step and rapidly deepens the gallery to 15 metres, where there is a small chamber of 5x6x4 metres; from this and to its left a short branch departs which is the continuation of the gallery through which the watercourse flows. This gallery of 5x6x4 metres at its start advances sinuously, where the water flows slowly between sandy deposits, and after about 100 metres its ceiling lowers until it forms a sump, which in exceptionally dry periods can be passed. At this point 2 branches can be taken; if the water is low enough one can continue in an open gallery following the fissuring, which becomes flattened until low passages of barely a handspan between water and rock are found. After 40 metres, a fork indicates an important inflow; in the direction of the current it leads 50 metres through a gallery of 1x0.5 metres, impenetrable at its end, where the water disappears. If one continues along the last-mentioned inflow, a new low-ceilinged gallery 1 metre high and 70 metres long leads through blocks and terraces of rounded pebbles to a chamber. This, 50x20x7 metres, has a floor with clastic fill beneath which the water inflow disappears; it is divided by a wall on its left side and, on both sides of this, a ramp gives access to its continuation. Here two piles of organic debris (leaves, branches, etc.) can be seen and vertically above is the G 2 entrance. Also in this chamber, on its S wall and at its ends, two branches of some length depart, running parallel to the chamber itself and to the active gallery by which it was reached. The continuation of the chamber is a little beyond the G 2 entrance: after a low passage a gallery is reached which brings an inflow of water flowing on the right. Following it downstream through a new low-ceilinged gallery of small dimensions one reaches the aforementioned chamber again at its W end and before climbing the also mentioned ramp that divides it. In turn, if one ascends upstream, a wide gallery with formations on the lateral ledges leads to a fork within a few metres where 2 branches end.

Returning to the fork before the sump and climbing a 2 metre step into a small gallery of semicircular section, after crawling several metres one reaches barriers of fossil gours. The end of one of them is the crawl or key passage of the cave, given its small dimensions: a passage in a circular basin with water and mud, normally semi-flooded, where the draught is usually felt. Once past it, a ramp allows one to reach a wider gallery and a chamber of 8x10 metres. From this point the water current can be reached by two places: a 2-3 metre downclimb or a fossil gallery. Both lead to the main gallery of the system, active, 3 metres wide and several high. After 230 metres of travel one reaches a chamber of 50x15 metres where at its start the active watercourse is lost. Later, crossing it, the watercourse is regained through a new descending gallery 23 metres wide and somewhat sinuous, which at 90 metres reaches a pothole pool in a vault, which is waded using a rope. From this point, 40 metres of wide gallery lead to a low passage between water and rock; after passing it, the gallery widens to connect at a junction of several branches. 1: to the left, a fossil gallery of about 100 metres in length which, after a sharp ascent and subsequent descent, short-circuits with a tunnel that emerges at the top of a ledge situated on the left in the aforementioned previous chamber 2. Straight ahead and on the other side of the current, by means of a steep ascending ramp, a series of crawls is reached, where one of them leads again to the river gallery metres back and at the height of the pool that is passed with a rope. Another of the crawls, the most interesting, excavated in limestone and meandering, reaches a wide gallery at a certain height above the floor (2 m) which brings a current of water. Little by little the gallery narrows with low passages, the last of which leads to a small chamber of circular plan, with a clay floor, where the current disappears. A climb to a balcony gives access to a descending crawl that narrows until continuation is prevented; a draught towards the outside is felt, continuous and interesting. It is at this point that in recent years the digging efforts have been focused to try to continue the explorations of the cave. 3: following the water current, a gallery 50 metres long gradually narrows until reaching a 2.5 metre step, a pool at its base and a further step beyond. Subsequently the gallery opens into a joint 4 metres wide and several high, where an inflow falls from the ceiling at this point, being lost through the same. A passage on the left reconnects with the water through a narrow gallery, and from here leaves, sticks and branches can be seen on the ceilings and walls, which shows that this part of the cave is sometimes flooded. After advancing a few metres through the water in a zone where there are large deposits of clay and sand, one reaches the end of the cave through a narrow, rather muddy crawl.

In the branches of the 50x20x7 metre chamber formations can be seen, as well as clay deposits. In the wide gallery that ascends upstream there are formations on the lateral ledges. Along the route barriers of fossil gours are found.

The streams found after the wooden bridge merge into one that reaches a flat-bottomed doline and sinks through a vertical fissure, the first entrance of Guardetxe. In the gallery of 5x6x4 metres the water flows slowly between sandy deposits and after about 100 metres its ceiling lowers until it forms a sump, passable in exceptionally dry periods. In the direction of the current, a gallery of 1x0.5 metres ends impenetrable where the water disappears. In the chamber of 50x20x7 metres, beneath the clastic fill of the floor the water inflow disappears. In the joint 4 metres wide, an inflow falls from the ceiling and is lost through the same. There are large deposits of clay and sand in the final zone traversed by the water.

From the Aralar forest house, the track heading North leads to a fork; take the left-hand one, marked with red marks, and after a small wooden bridge follow the streams to the doline and the first entrance. The main entrance, 1x2, leads to a meander; after a 3.5 metre step and a rapid descent to 15 metres one reaches a chamber of 5x6x4 metres. After about 100 metres the sump is reached; if the water is low enough one continues through an open gallery following the fissuring, with low passages of barely a handspan between water and rock. After 40 metres, at the fork, the direction of the current leads 50 metres through a gallery of 1x0.5 metres. Along the last-mentioned inflow, a low-ceilinged gallery 1 metre high and 70 metres long leads to the chamber of 50x20x7 metres. Its continuation is a little beyond the G 2 entrance, after a low passage. Following the water inflow downstream through a low-ceilinged gallery one returns to the chamber at its W end; upstream, a wide gallery leads to a fork where 2 branches end. From the fork before the sump one gains access by a 2 metre step to a small gallery of semicircular section and, after crawling several metres, to the barriers of fossil gours; the end of one of them is the crawl or key passage, in a circular basin with water and mud, normally semi-flooded. Once past this, a ramp leads to a wider gallery and to a chamber of 8x10 metres. From here the current is reached by a 2-3 metre downclimb or by a fossil gallery, both towards the main active gallery 3 metres wide. After 230 metres one reaches a chamber of 50x15 metres; crossing it the watercourse is regained through a descending gallery 23 metres wide, which at 90 metres reaches a pothole pool in a vault that is waded using a rope. From there, 40 metres of wide gallery lead to a low passage between water and rock and to a junction of several branches. To the left, a fossil gallery of about 100 metres short-circuits with a tunnel that emerges at the top of a ledge on the left of the previous chamber. Straight ahead, on the other side of the current, a steep ascending ramp leads to a series of crawls: one leads again to the river gallery metres back, at the height of the pool that is passed with a rope; another, the most interesting, excavated in limestone and meandering, reaches a wide gallery 2 m above the floor. Following the current, a gallery of 50 metres narrows to a 2.5 metre step, a pool at its base and a further step; then it opens into a joint 4 metres wide. A passage on the left reconnects with the water through a narrow gallery, and after advancing a few metres through the water one reaches the end of the cave through a narrow, rather muddy crawl.

Observations: topographic, biological and geological studies; biological and fossil finds. Total entrances to the system: 5. Survey: G.E.S.