During the last ten years, another cause has also largely contributed to the opening up of the great West. A dispute between the United States and Canada, as to the exact interpretation of the Treaty of 1818, led to the sending out of a joint commission to settle the matter, and mark out the boundary line between the north-west corner of the Lake of the Woods to the summit of the Rocky Mountains. The Commissioners, most of them able men of science, embodied in their report much interesting geographical information of a supplementary character, the most noteworthy points established being the vast extent of the Great Plains, with their strange, bewildering succession of mirages, rendering surveying operations extremely difficult; and the existence of a chain of salt lakes, with no outlet to the ocean, extending for fifteen miles in an east and west direction, near the very heart of the central watershed of the continent. Nine hundred miles were traversed in this successful trip, and the whole of the boundary line, now finally determined, was marked by stone cairns or earthen mounds, at intervals of three miles on the great plains, and by iron pillars one mile distant from each other for 135 miles through the southern prairie of Manitoba. These solitary landmarks, whether on the rich, fertile lands between the Lake of the Woods and the Pembina Mountains, the prairie steppe extending from the Pembina Mountains to the great Coteau of the Missouri, or the wild semi-desert stretching away from it to the Rocky Mountains, will soon, if we may so express it, be set in frameworks of colonization, for great and mighty are the changes which have taken place within the last few years. Emigration has more than kept pace with the advance of the Canadian Pacific Railway; the Red River settlers, no longer isolated from their kind, are at last enjoying the prosperity so long withheld; the number of settlers has increased rapidly since the opening of two outlets to the ocean for their produce; new settlements in the West are springing up as if by magic; a line of telegraph is completed between the ports on the banks of the Saskatchewan and the chief towns of Canada; while the long inaccessible solitudes of the northern range of the Rocky Mountains echo to the many sounds of the ever-increasing traffic along the line which has at last brought about the long-desired connection between the northern shores of the Atlantic and Pacific. Illustration: WINTER STATION FOR THE VESSELS OF THE ENGLISH PACIFIC SQUADRON. (_Esquimault._) INDEX.