by a storm, its prodigious hulk laboring in a gloomy sea of hornblendic granite, its deck-houses, shapen with perfect accuracy of imitation, still remaining in their place, and a weird-looking demon at the wheel steering it on to some invisible destruction.  This naval statue (if its bulk forbid not the name) was carved out of a coarse millstone-grit by the chisel of the wind, with but slight assistance from the infrequent rain-storms of this region.  In Colorado I first began to perceive how vast an omission geologists had been guilty of in their failure to give the wind a place in the dynamics of their science.  Depending for a year at a time, as that Territory sometimes does, upon dews and meltings from the snow-peaks for its water, it is nevertheless fuller than any other district in the world of marvellous architectural simulations, vast cemeteries crowded with monuments, obelisks, castles, fortresses, and natural colossi from two to five hundred feet high, done in argillaceous sandstone or a singular species of conglomerate, all of which owe their existence almost entirely to the agency of wind.  The arid plains from which the conglomerate crops out rarefy the superincumbent air-stratum to such a degree that the intensely chilled layers resting on the closely adjoining snow-peaks pour down to reestablish equilibrium, with the wrathful force of an invisible cataract, eight, ten, even seventeen thousand feet in height.  These floods of cold wind find their appropriate channels in the characteristic canons which everywhere furrow the whole Rocky-Mountain system to its very base.  Most of these are exceedingly tortuous, and the descending winds, during their passage through them, acquire a spiral motion as irresistible as the fiercest hurricane of the Antilles, which, moreover, they preserve for miles after they have issued from the mouth of the canon.  Every little cold gust that I observed in the Colorado country had this corkscrew character.  The moment the spiral reaches a loose sand-bed, it sweeps into its vortex all the particles of grit which it can hold.  The result is an auger, of diameter varying from an inch to a thousand feet, capable of altering its direction so as to bore curved holes, revolving with incalculable rapidity, and armed with a cutting edge of silex.  Is it possible to conceive an instrument more powerful, more versatile?  Indeed, practically, there is no description of surface, no kind of cut, which it is not capable of making.  I have repeatedly seen it in operation.  One day, while riding from Denver to Pike’s Peak, I saw it (in this instance, one of the smaller diameters) burrow its way six or seven feet into a sand-bluff, making as smooth a hole as I could cut in cheese with a borer, of the equal diameter of six inches throughout, all in less time than I have taken to describe it.  Repeatedly, on the same trip, I saw it gouge out a circular groove around portions of a similar bluff, and leave them standing as isolated columns, with heavy base and