The Union Pacific Railway, westward from Cheyenne in Wyoming, gradually ascends the slope and crosses the Continental Divide at Sherman, the pass being elevated eighty-two hundred and forty-five feet. Here, alongside the track, is the monument erected in memory of Oakes and Oliver Ames of Massachusetts, to whose efforts the construction of this pioneer railway across the Continent was largely due. Upon the western slope of the mountains the descent is to the Laramie Plains, an elevated plateau in Wyoming which is one of the best grazing districts of the country. In the midst of the region on the Big Laramie River is Laramie City, with ten thousand people, a prominent wool and cattle mart. To the north and west high mountains rise, out of which the river flows, and in this district is the great fossil region of Wyoming. This state is the most prolific producer of the skeletons of the enormous beasts that roamed the earth in prehistoric times. About ninety miles northwest of Laramie City are the greatest fossil quarries in existence, and the scientific hunters from all the great museums have been finding rich treasures there. We are told that in an early geological period Wyoming had numerous lakes and swamps and a semi-tropical climate. These huge animals then inhabited the lakes and swamps in large numbers. In dying, they sank into the mud, and their bones were covered by other deposits and became petrified. The extensive deposits of these bones are found where are supposed to have been the mouths of great water-courses, the huge animals, after death, having floated to where they are deposited in such large numbers. The belief is that through the geological eras these animals became covered with possibly twenty thousand feet of rock. Afterwards, the process by which the Rocky Mountains were formed tilted these rock beds, and the subsequent erosion of the strata brought to light these bone-deposits, made millions of years ago. For many years the scientists have been exhuming these skeletons, and have recovered the bones of over three hundred different species. They are of all sizes and characters, and here has been found the most colossal animal ever discovered on the earth, a dinosaur, nearly one hundred and thirty feet long, and thirty-five feet high at the hips and twenty-five feet at the shoulders. The skeleton of this immense creature, who is called a diplodocus, weighs twenty tons, and it is believed that when living he weighed sixty tons, having a neck thirty feet long and a tail twice that length. Yet his head was very small, and the weight of the brain was not over five pounds. In comparison with the mammoth, heretofore regarded as so large, this huge beast, whose foot covered a square yard of earth, was in size as a horse is compared to a dog. Such are the contributions Wyoming is making to our great museums of science.