animate nature. It is pleasant to have the bees come and suck honey out of my squash-blossoms, though, when they have laden themselves, they fly away to some unknown hive, which will give me back nothing in return for what my garden has given them. But there is much more honey in the world, and so I am content. Indian corn, in the prime and glory of its verdure, is a very beautiful vegetable, both considered in the separate plant, and in a mass in a broad field, rustling, and waving, and surging up and down in the breeze and sunshine of a summer afternoon. We have as many as fifty hills, I should think, which will give us an abundant supply. Pray Heaven that we may be able to eat it all! for it is not pleasant to think that anything which Nature has been at the pains to produce should be thrown away. But the hens will be glad of our superfluity, and so will the pigs, though we have neither hens nor pigs of our own. But hens we must certainly keep. There is something very sociable, and quiet, and soothing, too, in their soliloquies and converse among themselves; and, in an idle and half-meditative mood, it is very pleasant to watch a party of hens picking up their daily subsistence, with a gallant chanticleer in the midst of them. Milton had evidently contemplated such a picture with delight. I find that I have not given a very complete idea of our garden, although it certainly deserves an ample record in this chronicle, since my labors in it are the only present labors of my life. Besides what I have mentioned, we have cucumber-vines, which to-day yielded us the first cucumber of the season, a bed of beets, and another of carrots, and another of parsnips and turnips, none of which promise us a very abundant harvest. In truth, the soil is worn out, and, moreover, received very little manure this season. Also, we have cabbages in superfluous abundance, inasmuch as we neither of us have the least affection for them; and it would be unreasonable to expect Sarah, the cook, to eat fifty head of cabbages. Tomatoes, too, we shall have by and by. At our first arrival, we found green peas ready for gathering, and these, instead of the string-beans, were the first offering of the garden to our board. PHYSICAL HISTORY OF THE VALLEY OF THE AMAZONS. A YEAR or two ago I published in the Atlantic Monthly, as part of a series of geological sketches, a number of articles on the glacial phenomena of the Northern hemisphere. To-day I am led to add a new chapter to that strange history, taken from the Southern hemisphere, and even from the tropics themselves. I am prepared to find that the statement of this new phase of the glacial period will awaken among my scientific colleagues an opposition even more violent than that by which the first announcement of my views on this subject was met. I am, however, willing to bide my time; feeling sure that, as the theory of the ancient extension of glaciers in Europe has gradually come to be accepted by geologists, so will the existence of like phenomena, both in North and South America, during the same epoch, be recognized sooner or later as part of a great series of physical events extending over the whole globe. Indeed, when the ice period is fully understood, it will be seen that the absurdity lies in supposing that climatic conditions so intense could be limited to a small portion of the world's surface. If the geological winter existed at all, it must have been cosmic; and it is quite as rational to look for its traces in the Western as in the Eastern hemisphere, to the south of the equator as to the north of it. Impressed by this wider view of the subject, confirmed by a number of unpublished investigations which I have made during the last three or four years in the United States, I came to South America, expecting to find in the tropical regions new evidences of a by-gone glacial period, though, of course, under different aspects. Such a result seemed to me the logical sequence of what I had already observed in Europe and in North America. VOL. XVIII. NO. 105. 4 I. On my arrival in Rio de Janeiro,the port at which I first landed in Brazil, my attention was immediately attracted by a very peculiar formation, consisting of an ochraceous, highly ferruginous sandy clay. During a stay of three months in Rio, whence I made many excursions into the neighboring country, I had opportunities of studying this deposit, both in the province of Rio de Janeiro and in the adjoining province of Minas Geraes. I found that it rested everywhere upon the undulating surfaces of the solid rocks in place, was almost entirely destitute of stratification, and contained a variety of pebbles and boulders. The pebbles were chiefly quartz, sometimes scattered indiscriminately throughout the deposit, sometimes lying in a seam between it and the rock below; while the boulders were either sunk in its mass or resting loose on the surface. At Tijuca, a few miles out of the city of Rio, among the picturesque hills lying to the southwest of it, these phenomena may be seen in great perfection. Near Bennett's Hotel - a favorite resort, not only with the citizens of Rio, but with all sojourners there who care to leave the town occasionally for its beautiful environs may be seen a great number of erratic boulders, having no connection whatever with the rock in place, and also a bluff of this superficial deposit studded with boulders, resting above the partially stratified metamorphic rock. Other excellent opportunities for observing this formation, also within easy reach from the city, are afforded along the whole line of the Railroad of Dom Pedro Segundo, where the cuts expose admirable sections, showing the red, unstratified, homogeneous mass of sandy clay resting above the solid rock, and often divided from it by a thin bed of pebbles. There can be no doubt, in the mind of any one familiar with similar facts observed in other parts of the world, that this is one of the many forms of drift connected with glacial action. I was, however, far from anticipating, when I first met it in the neighborhood of Rio, that I should afterwards find it spreading over the surface of the country, from north to south and from east to west, with a continuity which gives legible connection to the whole geological history of the continent. It is true that the extensive decomposition of the underlying rock, penetrating sometimes to a considerable depth, makes it often difficult to distinguish between it and the drift; and the problem is made still more puzzling by the fact that the surface of the drift, when baked by exposure to the hot sun, often assumes the appearance of decomposed rock, so that great care is required for a correct interpretation of the facts. A little practice, however, trains the eye to read these appearances aright, and I may say that I have learned to recognize everywhere the limit between the two formations. There is indeed one safe guide, namely, the undulating line, reminding one of roches moutonnées, and marking the irregular surface of the rock on which the drift was accumulated; whatever modifications the one or the other may have undergone, this line seems never to disappear. Another deceptive feature, arising from the frequent disintegration of the rocks and from the brittle character of some of them, is the presence of loose fragments, which simulate erratic boulders, but are in fact only detached masses of the rock in place. A careful examination of their structure, however, will at once show the geologist whether they belong where they are found, or have been brought from a distance to their present resting-place. But while the features to which I have * The name consecrated by De Saussure to designate certain rocks in Switzerland, which have had their surfaces rounded under the action of the glaciers. Their gently swelling outlines are thought to resemble sheep resting on the ground, and for this reason the people in the Alps call them roches moutonnées. alluded are unquestionably drift phenomena, they present in their wider extension, and especially in the northern part of Brazil, as will hereafter be seen, some phases of glacial action hitherto unobserved. Just as the investigation of the ice period in the United States has shown us that ice-fields may move over open level plains, as well as along the slopes of mountain valleys, so does a study of the same class of facts in South America reveal new and unlooked-for features in the history of the ice period. Some will say, that the fact of the advance of ice-fields over an open country is by no means established, inasmuch as many geologists believe all the so-called glacial traces, viz. striæ, furrows, polish, etc., found in the United States, to have been made by floating icebergs at a time when the continent was submerged. To this I can only answer, that in the State of Maine I have followed, compass in hand, the same set of furrows, running from north to south in one unvarying line, over a surface of one hundred and thirty miles from the Katahdin Iron Range to the sea-shore. These furrows follow all the inequalities of the country, ascending ranges of hills varying from twelve to fifteen hundred feet in height, and descending into the intervening valleys only two or three hundred feet above the sea, or sometimes even on a level with it. I take it to be impossible that a floating mass of ice should travel onward in one rectilinear direction, turning neither to the right nor to the left, for such a distance. Equally impossible would it be for a detached mass of ice, swimming on the surface of the water, or even with its base sunk considerably below it, to furrow in a straight line the summits and sides of the hills, and the beds of the valleys. It would be carried over the depressions without touching bottom. Instead of ascending the mountains, it would remain stranded against any elevation which rose greatly above its own basis, and, if caught between two parallel ridges, would float up and down between them. Moreover, the action of solid, unbroken ice, moving over the ground in immediate contact with it, is so different from that of floating icerafts or icebergs, that, though the latter have unquestionably dropped erratic boulders, and made furrows and striæ on the surface where they happened to be grounded, these phenomena will easily be distinguished from the more connected traces of glaciers, or extensive sheets of ice, resting directly upon the face of the country and advancing over it. There seems thus far to be an inextricable confusion, in the ideas of many geologists, as to the respective action of currents, icebergs, and glaciers. It is time they should learn to distinguish between classes of facts so different from each other, and so easily recognized after the discrimination has once been made. As to the south ward movement of an immense field of ice, extending over the whole north, it seems inevitable, the moment we admit that snow may accumulate around the pole in such quantities as to initiate a pressure radiating in every direction. Snow, alternately thawing and freezing, must, like water, find its level at last. A sheet of snow ten or fifteen thousand feet in thickness, extending all over the northern and southern portions of the globe, must necessarily lead, in the end, to the formation of a northern and southern cap of ice, moving toward the equator. an abrupt ascents; as, for instance, on the Corcovado, along the path leading up the mountain, are some very fine banks of drift, the more striking from the contrast of their deep red color with the surrounding vegetation. I have myself followed this sheet of drift from Rio de Janeiro to the top of the Serra do Mar, where, just outside the pretty town of Petropolis, the river Piabanha may be seen flowing between banks of drift, in which it has excavated its bed; thence I have traced it along the beautiful macadamized road leading to Juiz de Fora in the province of Minas Geraes, and beyond this to the farther side of the Serra da Babylonia. Throughout this whole tract of country, in the greater part of which travelling is easy and delightful, admirable line of diligences, over one of the finest roads in the world, being established as far as Juiz de Fora, — the drift may be seen along the roadside, in immediate contact with the native crystalline rock. The fertility of the land, also, is a guide to the presence of drift. Wherever it lies thickest over the surface, there are the most flourishing coffee-plantations; and I believe that a more systematic regard to this fact would have a most beneficial influence upon the agricultural interests of the country. No doubt the fertility arises from the great variety of chemical elements contained in the drift, and the kneading process it has undergone beneath the gigantic ice-plough, a process which makes glacial drift everywhere the most fertile soil. Since my return from the Amazons, my impression as to the general distribution of these phenomena has been confirmed by the reports of some of my assistants, who have been travelling in other parts of the country. Mr. Frederick C. Hartt, accompanied by Mr. Copeland, one of the volunteer aids of the expedition, has sometimes reduced to a thin been making collections and geological layer, sometimes, as, for instance, on observations in the province of Spiritu steep slopes, washed entirely away, Santo, in the valley of the Rio Doce, leaving the bare face of the rock ex- and afterwards in the valley of the Muposed. It has, however, remained com- cury. He informs me that he has paratively undisturbed on some very found everywhere the same sheet of I have spoken of Tijuca and the Dom Pedro Railroad as favorable localities for studying the peculiar southern drift; but one meets it in every direction. A sheet of drift, consisting of the same homogeneous, unstratified paste, and containing loose materials of all sorts and sizes, covers the country. It is of very uneven thickness, — sometimes thrown into relief, as it were, by the surrounding denudations, and rising into hills, |