Mason (_Origin of Inventions_, page 192) has described such a kind of cultivation which was in existence amongst the American Indians quite recently. "A company of Cocopa or Mohave or Pima women set forth to a rich and favoured spot on the side of a cañon or rocky steep. They are guarded by a sufficient number of men from capture or molestation. Each woman has a little bag of gourd seed, and when the company reach their destination she proceeds to plant the seeds one by one in a rich cranny or crevice where the roots may have opportunity to hold, the sun may shine in, and the vines with their fruit may swing down as from a trellis. The planters then go home and take no further notice of their vines until they return in the autumn to gather the gourds" (E. Palmer). There is an interesting point about the cultivation of those early savage peoples who built up for themselves unhealthy but elaborate wooden dwellings in the Swiss lakes, in order to escape wild beasts and human beings who were even more dangerous and ferocious than they. Weeds occurred in those cornfields, cultivated by stone implements, some 60,000 years ago. The seed of an Italian weed had been introduced with their corn, and was discovered in Switzerland! Weeds are an extremely interesting group. A proverb about the hardiness and multiplication of weeds can be discovered in almost every language. "Ill weeds grow apace," _Unkraut verbessert nicht_, and so on. They are very common. In fact weeds, wayside, and freshwater plants, have by far the widest distribution of all. There are twenty-five species which can be found over at least half the entire land surface of the earth, and more than a hundred occupy a third of it.[122] [122] Drude, _Handbuch Pflanzengeographie_, p. 107. Moreover, many of our common weeds existed in Britain when the glaciers and ice melted away, and there were as yet no people able to cultivate the ground. The Creeping Buttercup, Chickweed, Mint, Persicaria, Dock, and Sheep's Sorrel had already colonized the country, before the Great Ice Age came upon them, and at least fourteen weeds were here when the first corn-raising savages landed in Britain.[123] [123] Reid, _Origin of the British Flora_. At first sight it is difficult to understand where and how they lived. One discovers a very few, however, if one botanizes very carefully along the seashore, or on river banks where landslips have occurred, and in other such places where bare ground exists which is not the result of cultivation. There these weeds fulfil a very important and useful purpose. The "red smear" of a landslip is soon tinted green with Coltsfoot, Chickweed and the like, and the bare earth, which was useless and supported no green covering, is very soon made once more a part of the earth's fruitful field. In such places the weeds are soon overcome and suppressed by the regular woods, grass, or thicket of the district.