The grotto of Gargas is located in Mount Tibiran about three hundred yards above the level of the valley, and about two miles southeast of the village of Aventignan. Access to it is easy, since a road made by Mr. Borderes in 1884 allows carriages to reach its entrance.
This grotto is one of the most beautiful in the Pyrenees, and presents to the visitor a succession of vast halls with roofs that are curved like a dome, or are in the form of an ogive, or are as flat as a ceiling. It is easy to explore these halls, for the floor is covered with a thick stalagmitic stratum, and is not irregular as in the majority of large caves.
Upon entering through the iron gate at the mouth of the grotto, one finds himself in Bear Hall, wherein a strange calcareous concretion offers the form of the carnivorous animal after which the room is named. This chamber is about 80 feet in width by 98 in length. We first descend a slope formed of earth and debris mostly derived from the outside. This slope, in which are cut several steps, rests upon a hard, compact, and crystalline stalagmitic floor. Upon turning to the right, we come to the Hall of Columns, the most beautiful of all. Here the floor bristles with stalagmites, which in several places are connected with the stalactites that depend from the ceiling. This room is about 50 feet square. After this we reach the Hall of Crevices, 80 feet square, and this leads to the great Hall of Gargas, which is about 328 feet in length by 80, 98, and 105 in width. In certain places enormous fissures in the vault rise to a great height. Some of these, shaped like great inverted funnels, are more than 60 yards in length. The grotto terminates in the Creeping Hall. As its name indicates, this part of the cave can only be traversed by lying flat upon the belly.
It gives access to the upper grotto through a narrow and difficult passage that it would be possible to widen, and which would then allow visitors to make their exit by traversing the beautiful upper grotto, whose natural entrance is situated 150 yards above the present one. This latter was blasted out about thirty years ago.
Upon following the direction of the great crevices, we reach a small chamber, wherein are found the Oubliettes of Gargas - a vertical well 65 feet feet in depth. The aperture that gives access to this strange well (rendered important through the paleontological remains collected in it) is no more than two feet in diameter. Such is the general configuration of the grotto.
In 1865 Dr. Garrigou and Mr. De Chastaignier visited the grotto, and were the first to make excavations therein. These latter allowed these scientists to ascertain that the great chamber contained the remains of a quaternary fauna, and, near the declivity, a deposit of the reindeer age.
As soon as it was possible to obtain a permit from the Municipal Council of Aventignan to do so, I began the work of excavation, and the persistence with which I continued my explorations led me to discover one of the most important deposits that we possess in the chain of the Pyrenees. My first excavations in Bear Hall were made in 1873, and were particularly fruitful in an opening 29 feet long by 10 wide that terminates the hall, to the left. I have remarked that these sorts of retreats in grottoes are generally rich in bones. Currents of water rushing through the entrance to the grotto carry along the bones - entire, broken, or gnawed - that lie upon the ground. These remains are transported to the depths of the cave, and are often stopped along the walls, and lie buried in the chambers in argillaceous mud. Rounded flint stones are constantly associated with the bones, and the latter are always in great disorder. The species that I met with were as follows: the great cave bear, the little bear, the hyena, the great cat, the rhinoceros, the ox, the horse, and the stag.
The stalagmitic floor is 1½, 2, and 2¼ inches thick. The bones were either scattered or accumulated at certain points. They were generally broken, and often worn and rounded. They appeared to have been rolled with violence by the waters. The clay that contained them was from 3 to 6 feet in thickness, and rested upon a stratum of water-worn pebbles whose dimensions varied from the size of the fist to a grain of sand. A thick layer of very hard, crystalline stalagmite covers the Hall of Columns, and it was very difficult to excavate without destroying this part of the grotto.
I found that there anciently existed several apertures that are now sealed up, either by calcareous concretions or by earthy rubbish from the mountain. One of these was situated in the vicinity of the present mouth, and permitted of the access to Bear Hall of a host of carnivora that found therein a vast and convenient place of shelter.
These excavations revealed to me at this entrance, at the bottom of the declivity, a thick stratum of remains brought thither by primitive man. This deposit, which was formed of black earth mixed with charcoal and numerous remains of bones, calcined and broken longitudinally for the most part, contained rudely worked flint stones. I collected a few implements, one surface of which offered a clean fracture, while the other represented the cutting edge. According to Mr. De Mortillet, such instruments were not intended to have a handle. They were capable of serving as paring knives and saws, but they were especially designed for scraping bones and skins. The deposit was from 26 to 32 feet square and from 2 inches to 5 feet deep, and rested upon a bed of broken stones above the stalagmite. The animals found in it were the modern bear (rare), the aurochs, the ox, the horse, and the stag - the last four in abundance.
At the extremity of the grotto there is a well with vertical sides which is no less than 65 feet in depth. It is called the Gargas Oubilettes. Its mouth is from 15 to 24 inches in diameter, and scarcely gives passage to a man (Fig. 1). Mr. Borderes, in the hope of discovering a new grotto, was the first to descend into this well, which he did by means of a rope ladder, and collected a few bones that were a revelation to me. Despite the great difficulty and danger of excavating at this point, I proceeded, and found at the first blow of the pick that there was here a deposit of the highest importance, since all the bones that I met with were intact. The first thing collected was an entire skull of the great cave bear, with its maxillaries in place. From this moment I began a series of excavations that lasted two years.
The descent is effected through a narrow vertical passage 6½ feet in length. The cavity afterward imperceptibly widens, and, at a depth of 12 yards, reaches 6½ feet in diameter, and at 15 yards 10 feet. Finally, in the widest part (at a depth of 62 feet) it measures about 16 feet (Fig. 1).
A glance at the section of the well, which I have drawn as accurately as possible (not an easy thing to do when one is standing upon a rope ladder), will give an idea of the form of this strange pocket formed in the limestone of the mountain through the most complex dislocations and erosions. Two lateral pockets attracted my attention because of the enormous quantity of clay and bones that obstructed them. The first, to the left, was about 15 feet from the orifice. When we had entirely emptied it, we found that it communicated with the bottom of the well by a narrow passage. An entire skeleton of the great cave bear had stopped up this narrow passage, and of this, by the aid of a small ladder, we gathered the greater part of the skeleton, the state of preservation of which was remarkable.
The second pocket, which was almost completely filled with clay, and situated a little lower than the other, likewise communicated with a third cavity that reached the bottom of the well. The clay of these different pockets contained so large a quantity of bones that we could hardly use our picks, and the excavation had to be performed with very short hooks, and often by hand. In this way I was enabled to remove the bones without accident. The lower pocket was dug out first, and with extreme care, the bones being hoisted out by means of a basket attached to a rope. Three or four candles sufficed to give us light. The air was heavy and very warm, and, after staying in it for two hours, it was necessary to come to the surface to breathe. After extracting the bones from the lower pocket, and when no more clay remained, we successively dug out the upper ones and threw the earth to the bottom of the well.
On the 20th of December, 1884, my excavating was finished. To-day the Oubliettes of Gargas are obstructed with the clay that it was impossible to carry elsewhere. The animals that I thus collected in the well were the following: The great bear (in abundance), the little bear (a variety of the preceding), the hyena, and the wolf. The pockets contained nearly entire skeletons of these species. How had the animals been able to penetrate this well? It is difficult to admit that it was through the aperture that I have mentioned. I endeavored to ascertain whether there was not another communication with the Gargas grotto, and had the satisfaction of finding a fissure that ended in the cave, and that probably was wider at the epoch at which the place served as a lair for the bear and hyena.
Very old individuals and other adults, and very young animals, were living in the grotto, and, being surprised, without power to save themselves, by a sudden inundation, reached the bottom of the well that we have described. The entire remains of these animals were carried along by the water and deposited in the pockets in the rock. Once buried in the argillaceous mud, the bones no longer underwent the action of the running water, and their preservation was thence secured. - F. Regnault, in La Nature.