The stalagmitic floor is 11/2, 2, and 21/4 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.

[Illustration:  Fig. 2.—­Skeleton of the cave hyena.]

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 61/2 feet in length.  The cavity afterward imperceptibly widens, and, at a depth of 12 yards, reaches 61/2 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).