The Subterranean World

by G. Hartwig

In addition to the peat-mosses, the Danish ‘shell-mounds’ throw some light on the prehistoric ages of that northern land. These mounds, or ‘refuse-heaps,’ consisting chiefly of thousands of cast-away shells of the oyster, cockle, and other molluscs of existing species, may be seen at certain points along the shores of nearly all the Danish islands. The shells are plentifully mixed up with the bones of various quadrupeds, birds, and fishes, which served as the food of the savages by whom the mounds were accumulated, while scattered all through them are rude implements of stone, horn, wood, and bone, with fragments of coarse pottery, mixed with charcoal and cinders, but never any implements of bronze or of iron. Similar refuse-heaps are found near the huts of many wild nations of the present day, as, for instance, near the miserable wigwams of the Fuegians, who live chiefly upon limpets.

The most striking proof that the Danish refuse-heaps are very old is derived from the character of their imbedded shells. These, indeed, belong entirely to living species, but the common eatable oyster is now unknown in the brackish waters of the Baltic, and the eatable mussels, cockles, and periwinkles, which in the refuse-heaps are as large as those which grow in the open sea, now only attain a third of their natural size. Hence we may confidently infer that in the days when the savage inhabitants of the Danish coasts accumulated these heaps, the ocean must have had freer access than now to the Baltic, and mixed its waters through broader channels with those of that inland sea.

As in the peat-bogs the implements and weapons found buried with the Scotch fir are all made of stone, whereas those coinciding with the oak epoch are made of bronze, we may farther conclude that the stone hatchets and knives of the refuse-heaps likewise belong to the same distant period when evergreen forests flourished in the Danish isles.

The ancient Swiss lacustrine dwellings, so frequently mentioned of late years, afford us another highly interesting glimpse into remote prehistoric ages. They seem first to have attracted attention during the dry season of 1853–4, when the lakes and rivers were unusually low, and when the inhabitants of Meilen on the Lake of Zurich resolved to raise the level of some ground, by throwing upon it the mud obtained by dredging in the adjoining shallow water. During these dredging operations they discovered a number of wooden piles deeply driven into the bed of the lake, and, among them, many stone instruments, fragments of rude pottery, fishing gear, and the bones of various animals; those which contained marrow being split open, in the same way as those found in the Danish shell-mounds.[^[31]]

The ruins thus unexpectedly brought to light were evidently those of a village of unknown date, and since then many other hill-dwellings (more than a hundred and fifty in all) have been detected near the borders of the Swiss lakes, at points where the depth of water does not exceed fifteen feet. Such aquatic sites were probably selected as places of safety, since they could be approached only by a narrow bridge or by boats, and the water would serve for protection alike against wild animals and human foes. The relative age of the pile-dwellings is clearly illustrated by the nature of the relics that lie scattered among their ruins. In some, only bronze utensils or ornaments are found; in others all the articles are of stone. The former, indicating an advance in civilisation, are evidently of a more recent age, but, even among the villages of the stone period, some are of later date than others, as they exhibit signs of an improved state of the arts. Thus we have here a long perspective into an unknown past, for even the bronze villages are probably of an age long antecedent to the Roman period. The oldest stone settlements are perhaps as old as the times of the Danish refuse-heaps; but even among their ruins, some domesticated animals occur, namely, the ox, sheep, goat, and dog, and the appearance of three cereals indicates that the population had already made some progress in the agricultural arts. Amber ornaments, which could only have found their way from the Baltic, as also hatchets and wedges of jade, of a kind not occurring in Switzerland or in the adjoining parts of Europe, and which some mineralogists would derive from the East, prove the existence of an active commercial intercourse, even at that early age, which the Swiss archæologists and geologists carry back as far as 7,000 years.

In the basin of the Mississippi, and especially in the valley of the Ohio and its tributaries, many large mounds have been found, which have served in some cases for temples, in others for outlook or defence, and in others for sepulture. Some of these earthworks are on so grand a scale as to embrace areas of fifty or a hundred acres within a simple inclosure; and the solid contents of one mound are estimated at twenty millions of cubic feet, equal to about one-fourth of the bulk of the Great Pyramid of Egypt. From several of these repositories pottery and ornamental sculpture have been taken, as also weapons made of unpolished hornstone and various articles in silver and copper. An active commercial intercourse must have existed between the Ohio mound-builders and the natives of distant regions, as mica from the Alleghanies, sea-shells from the Gulf of Mexico, obsidian from the Mexican mountains, and implements made of native copper from Lake Superior, have been found among the buried articles.

The extraordinary number of the mounds implies a long period during which a settled agricultural population, considerably advanced in the industrial arts, occupied the fertile valleys or the alluvial plains in the basin of the Mississippi, covered, since then, with vast forests, and tenanted by wild hunters without any traditionary connexion with their more civilised predecessors. The epoch when this people flourished, or the adverse circumstances which swept them away, are all equally unknown; but the age and nature of the trees found growing on some of their earthworks afford at least some data for estimating the minimum of time which must have passed since the mounds were abandoned.

Trunks, displaying eight hundred rings of annual growth, have been cut down from them, and several generations of trees must have lived and died before the mounds could have been overspread with that variety of species which they supported when the white man first set foot in the valley of the Ohio. In a memoir on this subject, General Harrison, who was skilled in woodcraft, observes that ‘beyond all doubt no trees were allowed to grow so long as the earthworks were in use; and when they were forsaken, the ground, like all newly cleared ground in Ohio, would for a time be monopolised by one or two species of tree, such as the yellow locust and the black or white walnut. When the individuals which were the first to get possession of the ground had died out one after the other, they would in many cases, instead of being replaced by the same species, be succeeded (by virtue of the law which makes a rotation of crops profitable in agriculture) by other kinds, till at last, after a great number of centuries (several thousand years, perhaps), that remarkable diversity of species characteristic of North America, and far exceeding what is seen in European forests, would be established.’

In all the cases hitherto mentioned, the remains or relics of prehistoric man, however remote a date we may assign to them, have been found associated with fossil shells and mammalia of living species. In the instances I am now about to relate, we advance a step further back, and find man the contemporary either of extinct mammalia or such as could now no longer exist in the lands where once they throve. As the mere mention of the numerous caves in Belgium, England, France, and Germany, in which human bones or articles of human workmanship have been found embedded along with the fossil remains of extinct animals, would tire the reader’s patience, I select from the number a few which have afforded the most convincing proofs of the antiquity of man. The credit of having given the first impulse to these fruitful investigations is due to the late Dr. Schmerling, of Liège, who, with untiring zeal, devoted several years of his life to the exploring of the ossiferous caverns which border the valley of the Meuse and its tributaries. To gain access to many of the caves was in itself no easy task, as their openings could be reached only by a rope tied to a tree; and when we consider that, after these arduous preliminaries, Dr. Schmerling had frequently to creep on all fours through contracted passages leading to larger chambers, there to superintend by torchlight, week after week, and year after year, the workmen who were breaking through a stalagmitic crust as hard as marble, in order to remove, piece by piece, the underlying bone breccia nearly as hard, and that while thus directing their labours he stood for hours with his feet in the mud, and with water dripping from the roof on his head, in order to mark the position and guard against the loss of each single bone which they brought to light, we can scarcely praise too highly his rare devotion to the cause of science.

Among these caverns thus laboriously explored, that of Engis was found to contain the remains of at least three human beings deeply buried under a thick floor of stalagmite. The skull of one of these, who may have been a beauty when the Meuse flowed at least fifty feet above its present channel, was embedded by the side of a mammoth’s tooth. Another skull was buried five feet deep in a breccia in which the tooth of a rhinoceros, several bones of a horse, and some of the reindeer, together with some ruminants, occurred. On the right bank of the Meuse, on the opposite side of the river to Engis, is the cavern of Engihoul, where likewise bones of extinct animals, mingled with those of man, were observed to abound; but with this difference, that whereas in the Engis cave there were several human crania and but very few other bones, in Engihoul there occurred numerous bones of the extremities belonging to at least three human beings, and only two small fragments of a cranium. None of the caves examined by Schmerling contained an example of an entire skeleton, and the bones were invariably so rolled and scattered as to preclude all idea of their having been intentionally buried on the spot. As no gnawed bones nor any coprolites were found, he inferred that the caverns of the province of Liège had not been the den of wild beasts, but that their organic and inorganic contents had been swept into them by streams communicating with the surface of the country. In 1860 Sir Charles Lyell, on a visit to Liège, determined still further to examine the Cave of Engihoul, into which Schmerling had delved in 1831, and engaged some workmen to break through the crust of stalagmite with the intention of searching for bones in the undisturbed earth beneath. Bones and teeth of the cave-bear were soon found, and, at the depth of two feet below the crust of stalagmite, three fragments of a human skull, and two perfect lower jaws with teeth, all associated with the bones of bears, large pachyderms and ruminants, and so precisely resembling these in colour and state of preservation as to leave no doubt that man was contemporary with the extinct animals.