launching of some canoes, on which the natives had been working for a long time. One of the party, during the feast, drew a number of figures resembling those M. Maclay had seen, and evidently referring to the work in hand. The two boats were represented as they were, half on land and half in water; then followed representations of men carrying pigs, the "covers" of the feast, M. Maclay's canoe with its flag, and the canoes of the visiting guests. Further evidence has made it tolerably clear that such representations are real ideographs. The carvings on wood, to which a religious bearing is ascribed, seem to show a regular progress toward sculpture, by the transformation of simple decorations into bas-relief, then into alto rilievo, and finally into the complete figure.
Plant-Migrations.—An interesting monograph has been published at the University of Giessen, Germany, on the migrations of two plants, the Puccinea malvacearum, or mallows fungus, and the Elodea Canadensis (Anacharis Canadensis, Gray). The former plant was first noticed infesting the mallows-plants of Chili. It was observed in Spain, for the first time in Europe, in 1869, having, it is thought, been introduced in the course of trade. Next it was found in France, infesting some ten species of the mallows family, in 1872, 1873, and 1874; it appeared in England in 1873, and was carried to Holland and Belgium in 1874. It was also found at the Cape of Good Hope and in Australia in 1874. It began to attract attention in Germany and Italy in 1874, and appears now to be diffused all over Europe, as its presence is mentioned in Bohemia and Hungary and at Athens, which appears so far to mark its southeastern point of extension. The Elodea, or Anacharis Canadensis, was noticed in single localities in Ireland in 1836 and 1842. Toward 1850 it became quite abundant, and in the course of the next ten years found its way to the Botanical Gardens of Utrecht and the swamps in the neighborhood of Ghent. It was growing in several places in France in 1866. It is now found in considerable abundance in the lower Rhine, the Elbe and its branches, the Havel and Spree, and the Oder. It has extended from Corrib, Ireland, on the west, and Grenoble, France, on the south, to Riga, on the northeast. It has been carried by sprouts to all the places where it grows; for only female plants (not a single male plant) are to be found in all Europe.
Efficiency of Present Causes in Geological Action.—M. Stanislas Meunier has recently published a work discussing the sufficiency of the causes which are still in operation to account for the production of the geological phenomena of the past. Illustrations of the principle involved in the discussion may easily be found in examining some of the formations near the surface. In the section of the coal-beds of Valenciennes, thick, horizontal cretaceous beds appear, resting on carboniferous beds, the strata of which are contorted, bent, and folded neither more nor less than the strata of which the highest mountain-chains are composed. As the contact of the chalk and the coal is horizontal, it must be admitted that, previous to the deposit of the secondary rocks, the ground, which had been greatly disturbed by the foldings of the carboniferous strata, had been again planed down to a level. The first thought would be to attribute the planing down to some sudden and violent action carrying away all of the missing matter at once. The view is entirely changed when we remark that quite as important denudations are taking place now in populous districts without any perturbations of a violent character. Thus, on the British coast of the English Channel the sea is gaining about a yard a year upon the land, and the fact is recognized in sales. The result of this denudation, which is taking place so gradually, can not be distinguished from that of a sudden razing of the strata at the bottom of the sea. M. Meunier examines likewise the theory that river-valleys have been formed by the action of streams in a period of floods, when they were many times larger than the present rivers. The valleys of the rivers, he believes, correspond with original fractures of the soil; this once accepted, we may admit that the stream was neither much more voluminous nor much more rapid in quaternary times than at present. In the course of an indeterminate period of time it has widened
