it is now understood that all caves have originated. Owing to many natural causes the river may, after a while, cease to flow, leaving enlarged portions of its channel behind as a succession of chambers in a cave. But water would still come trickling in from the tops and sides, and be continuously dripping to the floor, where it speedily evaporates. When such is the case it leaves behind it the limestone it held in solution. So, in process of time, if the deposition is undisturbed, there will be formed over the floor of the cave a more or less continuous layer of limestone matter known as stalagmite. The same formations on the top and sides of the cave are called stalactites. In places where the drip is continuous the stalactite gradually assumes the shape of an immense icicle; while the stalagmite on the floor of the cave, underneath the drip, rises in a columnar mass to meet the descending stalactite. A union of these is not uncommon, and, we have pillars and columns presenting the strange, fantastic appearance on which tourists delight to dwell in their notes of travel. While these accumulations are in all cases very slow, still we can not measure the time since it commenced by the rate of present growth, because this rate varies greatly at different times and places even in the same cave. And we must also remark that this complete series of changes only occur in a few localities, the majority of caves being insignificant in size. 110 From what has been said as to the formation of caves, we would expect them to occur in river valleys, and this is the case, though in some instances there have been such immense changes in the surface level of the country that we can now find no trace of rivers near them. This is exactly similar to some gravel deposits, which, as we have seen, are occasionally found where is now no running water. The most noted caverns, however, are found high up on the banks of existing rivers. We can not doubt that the rivers were the cause of the caves. But having excavated their beds below the level of the then existing caves, they ceased to flow in them, and left them to be occupied by savage animals and the scarcely less savage men. But at times, swollen by floods, the river would again assert its supremacy and roll its waters through its old channels. These floods would not only tear up and rearrange whatever
debris had already accumulated, but would introduce quantities of sediment and animal remains. In some such a manner as is here pointed out (though exactly how geologists are not agreed) caves were invaded, after being long occupied by men or animals, by floods of water. In many cases the evidence would seem to indicate that after such a visitation by water the cave and its water-rolled and water-arranged contents were left to silence, visited by neither man nor beast. In such instances stalagmitic coverings would gradually form over the confused
debris, and in some places acquire a thickness of several feet. In some instances several such floors are found one above the other, pointing to a prolonged period of usage, and then a quiet stage, in which the drip of falling water alone broke the silence, and nature sealed up another chapter of cave biography beneath the layer of stalagmite. 111 One of the most important caves of England is Kent's Cavern, before mentioned. This cave was carefully explored under the direction of a committee appointed by the British Association, and to show the care and thoroughness of the work we need only state that this work occupied the greater portion of sixteen years, and hence the results obtained may be regarded as, in a general way, illustrative of the life of the cave dwellers. "This cave is about a mile east of Torquay harbor, and is of a sinuous character, running deeply into a hill of Devonian limestone, about half a mile distant from the sea. In places it expands into large chambers, to which various distinctive names have been given." Let us see what general results have been reached by this committee. The investigation disclosed several different beds of stalagmite, cave earth, and breccia. The lowest layer is a breccia. The matrix is sand of a reddish color, containing many pieces of rock known as red-grit and some pieces of quartz. This implies the presence of running water, which at times washed in pieces of red-grit. The surface features must have been quite different from the present, since now this rock does not form any part of the hill into which this cave opens. And this change in drainage took place before this lowest layer was completed, since not only bears, but men, commenced to visit the cave. The presence of bears is shown by numerous bones, and that of man by his implements. Illustration of Spear-head--Lower Breccia, Kent's Cavern.--- We must notice that all the implements found in the breccia are similar 112 to those of the Drift, being rudely formed and massive. No doubt these are the remains of Drift men, who, for some cause or other, temporarily visited the cave, perhaps contending with the cave bear for its possession. But a time at length arrived when for some reason neither animals nor man visited the cave. The slow accumulation of stalagmite went forward until in some places it had obtained a thickness of twelve feet. Freely admitting that we can not determine the length of time demanded for this deposition, yet none can doubt that it requires a very long time indeed. Says Mr. Geikie: "How many centuries rolled past while that old pavement was slowly accreting, no one can say; but that it represents a lapse of ages compared to which the time embraced by all tradition and written history is but as a few months, who that is competent to form an opinion can doubt?" But after this long period of quiet, from some source great torrents of water came rolling through the cave. We know this to be so, because in places it broke up this layer of stalagmite and washed it away, as well as large portions of the breccia below, and after the floods had ceased, occasionally inundations still threw down layers of mud and silt. This accumulation is known as cave earth, and is the layer containing the numerous remains of the Cavemen. Here the explorers were not only struck with the large number of implements, but at once noticed that they were of a higher form and better made. Instead of the rude and massive implements of the Drift tribes, we have more delicate forms chipped all around. And we also meet with those that from their form may have been used as the heads of spears or arrows. Flakes were also utilized for various pur implements, weapons, and ornaments of bone--a step in advance of Drift culture. They had "harpoons for spearing fish, eyed needles or bodkins for stitching skins together, awls perhaps to facilitate the passage of the slender needle through the tough, thick hides; pins for fastening 113 the skins they wore, and perforated badgers' teeth for necklaces or bracelets." Nothing of this kind has yet been shown as belonging to the men of the Drift. Illustrations of Spear-head and Flake----------- The bones of a large number of animals are also found in the cave earth. The most abundant is the hyena, and no doubt they dragged in a great many others; but the agency of man is equally apparent, as the bones have often been split for the extraction of marrow. Besides bones of the hyena, we have also those of the lion, tiger, bear, and reindeer. Illustration of Harpoons, Pin, Awl, and Needle--Kent's Cavern. With these animals man, from time to time, disputed possession of the cave. At one place on the surface of the cave earth is found what is known as the "black band." This is nothing more or less than the fireplace of these old tribes. Here we find fragments of partially consumed wood, bones showing the action of fire--in short, every thing indicating a prolonged occupancy by man. No one can doubt but that this deposit of cave earth itself requires a prolonged time for its accumulation. But this period, however prolonged, at length comes to an end. From some cause, both animals and man again abandoned the cave. Another vast cycle of years rolls away--a 114 time expressed in thousands of years--during which nature again spread over the entombed remains a layer of stalagmite, in some places equal in thickness to the first formation. Above this layer we come to a bed of mold containing remains of the later Stone Age, of the Bronze, and even of the Iron Age. Below the first layer of stalagmite--the completed biography of Paleolithic times; above, the unfinished book of the present. Such are the eloquent results obtained by the thorough exploration of one cave. The results of all the other explorations, in a general way, confirm these. Mr. Dawkins explored a group of caverns in Derbyshire, England. These caverns and fissures are situated in what is known as Cresswell Crags, the precipitous sides of a ravine through which flows a stream of water dividing the counties of Derby and Nottingham. This cut represents the different strata in Robin Hood cave. It will be seen that, at one place, the stalactite has united with the stalagmite below. It is not necessary to go into the details of this exploration. All the relics of man found in
d, c, and the lower portions of
b, are the rude and massive forms peculiar to the River Drift tribes. But the relics found in the breccia
a, and the upper portion of the cave earth
b, denote a sudden advance in culture. The rude tools of the lower strata are replaced by more highly finished ones of flint. Illustration of Robin Hood Cave.----------- The most important discovery was that of a small fragment of rib, with its polished surface ornamented with the incised figure of a horse. 115 The peculiar value of this discovery is, that it serves to connect the Cavemen of England with those of the
