It should be understood that there are several passes through the lofty range it was our object to cross.  These passes had been formed by the mountains being rent asunder by some mighty convulsion of nature.  All of them are many miles in length, and in some places several in width; now the pass presents a narrow gorge, now expands into a wide valley. The highest point is called the watershed, where there is either a single small lake, or a succession of lakelets, from which the water flows either eastward through the Saskatchewan or Athabasca rivers, to find its way ultimately into the Arctic Ocean, or westward, by numberless tributaries, into the Fraser or Columbia rivers, which fall, after making numerous bends, into the Pacific.