As the train approached the spot where the herd was crossing the track, the locomotive gave its loudest and shrillest shrieks. The noise had the effect of frightening the buffaloes sufficiently to stop those which had not crossed, and in the gap thus formed the train moved on. The boys were greatly interested in the appearance of the beasts, and Frank declared he had never seen anything that looked more fierce than one of the old bulls, with his shaggy mane, his humped shoulders, and his sharp, glittering eyes. He was quite contented with the shelter of the railway-car, and said if the buffalo wanted him he must come inside to get him; or give him a good rifle, so that they could meet on equal terms. Several of the passengers fired at the buffaloes, but Fred was certain he did not see anything drop. In half an hour the train had passed through the herd, and was moving on as fast as ever. On and on they went. The Doctor pointed out many places of interest, and told them how the road was built through the wilderness. [Illustration: "END OF TRACK."] "It was," said he, "the most remarkable enterprise, in some respects, that has ever been known. The working force was divided into parties like the divisions of an army, and each had its separate duties. Ties were cut and hauled to the line of the road; the ground was broken and made ready for the track; then the ties were placed in position, the rails were brought forward and spiked in place, and so, length by length, the road crept on. On the level, open country, four or five miles of road were built every day, and in one instance they built more than seven miles in a single day. There was a construction-train, where the laborers boarded and lodged, and this train went forward every day with the road. It was a sort of moving city, and was known as the 'End of Track;' there was a post-office in it, and a man who lived there could get his letters the same as though his residence had been stationary. The Union Pacific Company built west from Omaha, while the Central Pacific Company built east from Sacramento. They met in the Great Salt Lake valley; and then there was a grand ceremony over the placing of the last rail to connect the East with the West. The continent was spanned by the railway, and our great seaboards were neighbors." [Illustration: SNOW-SHEDS ON THE PACIFIC RAILWAY.]