Such a system of disposing of the public lands in the Arid Region will necessitate an authoritative classification of the same. The largest amount of land that it is possible to redeem by irrigation, excepting those tracts watered by lone springs, brooks, and the small branches, should be classed as irrigable lands, to give the greatest possible development to this industry. The limit of the timber lands should be clearly defined, to prevent the fraudulent acquirement of these lands as pasturage lands. The irrigable and timber lands are of small extent, and their boundaries can easily be fixed. All of the lands falling without these boundaries would be relegated to the greater class designated as pasturage lands. It is true that all such lands will not be of value for pasturage purposes, but in general it would be difficult to draw a line between absolutely desert lands and pasturage lands, and no practical purposes would be subserved thereby. Fix the boundaries of the timber lands that they may be acquired by proper methods; fix the boundaries of the irrigable lands that they may also be acquired by proper methods, and then permit the remaining lands to be acquired by settlers as pasturage lands, to the extent that they may be made available, and there will be no fear of settlers encroaching on the desert or valueless lands. Heretofore we have been considering only three great classes of lands--namely, irrigable, timber, and pasturage lands, although practically and under the laws there are two other classes of lands to be recognized--namely, mineral lands, _i. e._, lands bearing lodes or placers of gold, silver, cinnabar, etc., and coal lands. Under the law these lands are made special. Mineral lands are withheld from general sale, and titles to the mines are acquired by the investment of labor and capital to an amount specified in the law. Coal lands are sold for $20 per acre. The mineral lands proper, though widely scattered, are of small extent. Where the mines are lodes, the lands lie along the mountains, and are to a greater or less extent valueless for all other purposes. Where the mines are placers, they may also be agricultural lands, but their extent is very limited. To withhold these lands from purchase and settlement as irrigable, timber, and pasturage lands will in no material way affect the interests of the industries connected with the last mentioned lands. The General Government cannot reasonably engage in the research necessary to determine the mineral lands, but this is practically done by the miners themselves. Thousands of hardy, skilful men are vigorously engaged in this work, and as mines are discovered mining districts are organized, and on the proper representation of these interested parties the mineral lands are withheld from general sale by the Land Department. Thus, proper provision is already made for this branch of the work of classification.