study of the tropical forest as interesting to the geologist as to the botanist, namely, its relation to the vegetable world of past ages hidden in the rocks. The tree-ferns, the Chamærops, the Pandanus, the Araucarias, are all modern representatives of past types, and this walk in the forest was an important one to Mr. Agassiz, because he made out one of those laws of growth which unite the past and the present. The Chamærops is a palm belonging to the ancient vegetable world, but having its representatives in our days. The modern Chamærops, with its fan-like leaves spreading on one level, stands structurally lower than the Palms with pinnate leaves, which belong almost exclusively to our geological age, and have numerous leaflets arranged along either side of a central axis. The young Palms were exceedingly numerous, springing up at every step upon our path, some of them not more than two inches high, while their elders towered fifty feet above them. Mr. Agassiz gathered and examined great numbers of them, and found that the young Palms, to whatever genus they may belong, invariably resemble the Chamærops, having their leaves extending fan-like on one plane, instead of being scattered along a central axis, as in the adult tree. The infant Palm is in fact the mature Chamærops in miniature, showing that among plants as among animals, at least in some instances, there is a correspondence between the youngest stages of growth in the higher species of a given type and the earliest introduction of that type on earth.[40]