The _valla_ include important works. One of them cuts across Valachie parallel with the Danube and loses itself in Southern Russia. Another crosses the north of Moldavia and Bessarabia, following a direction convergent with the former. These _valla_, although they are known in the country in which they occur as _Fossés de Trajan_, are certainly of earlier date than the Roman occupation, and in fact Roman roads cut across the intrenchments or fosses which have been levelled or covered over to make way for them. Excavations of the large tumuli are not yet sufficiently advanced for us to hazard an opinion about them. The smaller ones, however, are seldom of Roman origin. The funeral vases of calcareous stone which they contain bear witness clearly enough to their destination, and also to the rite with which they were connected. The _cetati de pamentu_ are regular earthen fortifications set up within short distances of each other on all the heights overlooking the torrential rivers of Roumania. These intrenchments, generally of round or oval form, are protected by deep fosses, parapets, and palisades. Masses of cinders and burnt earth bear unmistakable evidence to the cause of their destruction. All about, excavations have brought to light coarse pottery, grindstones for crushing grain, stores of millet which had been damaged by the flames, and a few primitively constructed bronze idols. When the vanquished Roumanians were driven from their intrenchments, they had evidently learned to use bronze, but were still, as we have already remarked, unacquainted with iron, as no object in that material has been found, nor does anything bear any trace of rust. Thus, throughout Europe, man, in the presence of the many dangers surrounding him, endeavored in the very earliest times to protect by similar means his family, his flocks, and his wealth. In America we are able to quote facts of even more importance. The vast territory comprised between the Alleghanies and the Rocky Mountains, between the great lakes of Canada and the Gulf of Mexico, is intersected with truly colossal fortifications, almost all of them made entirely of earth. The ancient Americans knew how to protect every height and every delta formed by the junction of two rivers with redoubts, walls, parapets, fosses, and circumvallations. Not without astonishment we make out a regular system of fortresses connected with each other by deep trenches and secret passages, some of them hewn out beneath the beds of rivers, observatories on the heights, and concentric walls, some actually strengthened with casemates protecting the entrances. All these works were constructed by the so-called Mound-Builders, of whose ancestors or of whose descendants absolutely nothing is known.