We have already enumerated the most important forms of weapons and implements found in these _tumuli_; and there would be no use in entering upon a lengthy verbal description of what would be so much better illustrated by drawings. The books enumerated in the Appendix give abundant illustrations of the stone-age remains. One caution, however, we need to give the reader. This second stone age is called, we know, the age of polished stone. But, as has been already said, that by no means implies that all the implements made in these days were polished. On the contrary, certain stone manufactures, notably arrow-heads, were never polished. They went on being made by chipping, not only during the whole of the second stone age, but far into the first metal age, when bronze had been introduced and was used for the manufacture of numerous weapons and implements. The grinding of the edges of certain sharp weapons is a more important characteristic than the polishing of the whole or a portion of their surface. But this grinding was not universally employed, but used generally only for the larger implements. * * * * * [Sidenote: The lake villages.] And now, having dealt with the remains from the _tumuli_, the flower, as we may call them, of the second stone period, we pass on to a third series of remains, which must be in part contemporary with the stone-using men, and have continued on and been absorbed into the metal age, which next supervened. These remains came from what are called the lake-dwellings, and though traces of such dwellings have been found in many countries in Europe, in our isles among others, still the chief _provenance_ of the lake-dwellings, so far as our discoveries yet go, is in Switzerland and the north of Italy. But let it not be supposed that these lake-dwellings extended over a short period. A variety of separate pieces of evidence enforce upon us the conclusion that the stone age in Europe endured for at least two thousand years. Even the latter portion of that epoch will allow a cycle vast enough for the lives of the lake-dwellers; for the dwellings did not come to an end at the end of the age of stone, they only began in it. They were seen by Roman eyes almost as late as the beginning of our own era.