In these imperfect vessels men gradually ventured further and further into the ocean; and, judging of the extent of their voyages by the deep-sea remains, we may be certain that their bravery was fatal to many. This is in all probability the history of the discovery or re-discovery of the art of navigation among savage people generally; in all cases does the canoe precede the regular boat. I say ‘re-discovery’ because a nation which has settled long inland might very easily lose the art even if their ancestors had possessed it. For it is a fact that people rarely begin attempts at ship-building before they come to live near the sea. As long as they can range freely on land, their rivers do not tempt them to any dangerous experiments. But the vast plain of the sea is too important, and makes too great an impression on their imagination for its charm to be long withstood. Sooner or later, with much risk of life, men are sure to try and explore its solitudes, and navigation takes its rise. This art of seafaring, then, is amongst the most noticeable of the belongings of the fishermen of the shell mounds. Considering that they had none but rude stone implements, the felling and hollowing of trees must have been an affair of no small labour, and very likely occupied a great deal of their time when they were not actually seeking their food, even though the agency of fire supplemented the ineffectual blows of their stone weapons. They probably used nets for their sea-fishing, made most likely of twisted bark or grass. And they were hunters as well as fishers, for it has been said that the remains of various animals have been discovered on the shell mounds. From these remains we see that the age of the post-glacial animals has by this time quite passed away; no mammoth, woolly rhinoceros, or cave lion or bear is found; even the reindeer, which in palæolithic days must have ranged over France and Switzerland, has retired to the north.