Across the United States, from Canada to Mexico, the advance line of farms pushed from the well-watered bottoms of the Mississippi Valley into the plains that rise toward the Rocky Mountains. Near the ninety-seventh meridian the rainfall of this region becomes insufficient for general farming in ordinary years. But the solicitations of land-sellers brought settlers into the sub-humid region, while for a few years in the eighties the rainfall was greater than the average. Permanent climatic changes were imagined by the hopeful. A Governor of Kansas stated, in 1886, "with absolute certainty, that great areas in the Western third of Kansas are becoming more fertile," while an Eastern Senator, who was generally well informed, believed in 1888 that "the whole Territory of Dakota is as capable of sustaining population as Iowa." Between the farming frontier and the mountains the cattlemen expanded the grazing industry, with profits that were enlarged because of the markets that the railroads brought them. The "long drive" from Texas to Montana became a familiar idea on the border, while the cowboys in their lonely watches developed a folk-song literature that is typically American. Between the cattlemen and the sheepmen there was permanent war, for the sheep injured the grass they grazed over. Although both industries were trespassers on the public lands the herders resented the appearance of the flocks as an intrusion upon their domain. Kansas City rose suddenly to prominence as the meeting-place of the railways of the West and Southwest with those of the East. Near to the line that divided steady agriculture from the nomadic life of the plains it became a convenient market for both. Here the packers developed the traffic in fresh beef that the new railways with their refrigerator cars made possible. The cities of the East, in need of more fresh meat than the local farmers could provide, found their supply on the plains of the Far West. Beyond the plains, the mountain regions changed less from the advent of the railways than any other section of the remote West. They had attracted population to their camps during the Civil War, and now they grew in size and permanence. But only such regions reached permanent importance as had valleys to be irrigated and fields to be cultivated. Without agriculture no important region has flourished in the West.