Of the present working localities the principal one is Mt. Pleasant, and while the property owners there are beginning to figure a little on how much they have left, still the prevailing impression that Mt. Pleasant is about through mining is an exceedingly mistaken one. With the present rate of output, the visible supply of the Mt. Pleasant field proper will last for seven years longer, without taking into consideration the Southport field, which is practically part of the Mt. Pleasant field. With the Southport field mining will last here at the present rate of output for eleven years. It is very easy to understand that as work progresses at Mt. Pleasant and the end comes more nearly in sight, some miners drop out by selling, some by working out their small deposits and these naturally go to the other fields above referred to. In none of the other fields is found the persistently uniform high grade brown rock of Mt. Pleasant except Southport, Century and Kleburn, in the two latter of which operations are now in progress, and in the former the extension of the Mt. Pleasant Southern Railway will soon cause development work there. As these deposits afford practically the same grade of rock as Mt. Pleasant proper, they will be worked out simultaneously with it and will cater to the same market. With their knowledge that the visible supply of this character of rock is comparatively limited, producers are gradually increasing their prices, and by reason of such increase they are slowly reducing their output and giving opportunity for the marketing of the lower grades in the other fields, notably the Swan Creek and Indian Creek deposits in Hickman County. This, of course, means that the producers at Mt. Pleasant will make more money from their product, and that it will last a considerably longer time, so that it is safe to say that mining in force will be carried on at Mt. Pleasant and kindred localities for at least twenty years. During the next decade, to supply the diminution of Mt. Pleasant’s output, will come the gradual development of the vast blue rock field of Maury, Hickman and Lewis counties, and the white rock of Perry and Decatur counties, which form the backbone of the phosphate industry in Tennessee, and whose millions of tons will cause these counties to be considered the phosphate reservoir of the world for the next seventy-five or one hundred years. The change of base will be gradual and easy, and the trade will have ample opportunity and time to adjust its operations so as to utilize the lower grade blue rock as it becomes advisable and necessary to do so. Its many points of superiority for acidulation and for direct use without acidulation will largely make up for its lower grade, and as a mining proposition it more nearly approaches a technical field of operation.