are cool in summer and warm in winter, but are superior to "adobe" dwellings in point of dryness and cleanliness. This superiority is due to the fact that wherever the soil is smoothly cut the slight chemical union, which speedily takes place under the influence of the atmosphere between the silica and the carbonate of lime, coats the surface as if with a light washing of cement, and so prevents crumbling. One may note spade-marks as clean-cut and fresh-looking as if newly made on the walls or ceiling of "dugouts" that have been occupied for years. When the threatened (?) "Mongolian invasion" comes, what hosts of happy Celestials will find here congenial homes! And if, for their better contentment, they rechristen the Missouri the Yellow River, it will be no serious misnomer.
In point of fertility our Western loess-beds are the counterpart of those described by Mr. Williams, except that they do not seem to suffer equally in seasons of drought. The greater depth of the Nebraska deposits—exceeding in many places two hundred feet—and, possibly, their more perfect capillary structure, may explain this difference.
As to the origin of the loess-beds of the United States, the belief of Drs.. Hayden, Aughey, and others that they are lacustrine deposits has been hitherto accepted. But it is curious to note how many of their peculiar characteristics are explained, and their general features harmonized with the geological and meteorological phenomena of the great region lying between them and the summit of the Rocky Mountains, by the hypothesis that they are subaërial rather than subaqueous deposits. Nearly all the arguments adduced by Baron von Richthofen in support of his theory of the origin of the loess-beds of Asia may be adduced with equal force, mutatis mutandis, in support of a like theory here. Of more than one hundred and twenty species of shells found and identified in the loess-deposits of Nebraska, as given by Dr. Aughey on pages 267 and 268 of "United States Geological Report" for 1874, it will be seen that a large proportion are land-shells. And it appears from the same "Report" that, while the deposits are rich in the remains of land-animals, no considerable number of aquatic species have ever been identified.
Dr. Aughey says, page 254: "Occasionally I have found the teeth and a stray bone of a fish, but have not been able to identify any species. The remains of rabbits, gophers, otters, beavers, squirrels, deer, elk, and buffalo are frequently found. Through the entire extent of these deposits are many remains of mastodons and elephants." To one who has ever encountered a dust-storm on the great plains west of these deposits, when the landscape to either horizon is obscured with flying clouds of powdery dust, like drifting fog, and has noted the almost continuous belt of sand-hills extending from Western Kansas through Eastern Colorado and Wyoming and Western Nebraska, evidently formed by these high winds, whose prevailing direction is always eastward, and marking the deposit of the heavier particles dropped from the flying mass of dust-freight which they had gathered in their fury from the arid foot-hills and high plains still farther westward, the theory of Von Richthofen commends itself with peculiar force. And if a period of still greater aridity be conceived of, before these high regions, the American analogues of the Asiatic steppes, had received their present scant protection of stunted grasses, the conviction arises that, even assuming the volume and velocity of the wind to have been no greater then than now, its prevailing direction being the same, our loess-deposits of the North-west, like those of China, may be accounted for, both as to their origin and chief peculiarities, by reference to known causes still existing, whose action has been, indeed, greatly modified but not wholly suspended; and without recourse, necessarily, to the lacustrine hypothesis.
|William T. Holt.|
|Denver, Colorado, January 4, 1884.|
THERE is obviously a decline in the influence of malign criticism in recent times. Even the savage "quarterly reviewer" has lost many of the terrors with which he used to be invested. An excellent example of this is afforded by the history of Spencer's "Synthetic Philosophy." It has been tempting game for the critical sports, and they have pursued it unweariedly. It had but few friends and multitudes of enemies. A new departure in philosophy, it incurred the hostility of the devotees of all old philosophies. Dealing with the larger aspects of science, it kindled the jealousy of narrow-minded scientific