On they went, day after day. July 1st they passed the mouth of what the Indians called the River of the Mountain, afterward known as the Liard, where Fort Simpson was built many years later. As they proceeded, it became clear to Mackenzie that the river down which he was paddling must empty into the Arctic--but would it be possible to reach the ocean and return to Fort Chipewyan that season? The men were beginning to get discouraged, and it required all Mackenzie’s enthusiasm and strength of purpose to keep them to the strenuous task. The tribes they met as they went north--Slaves and Dog-ribs and Hare Indians--did not prove as ferocious as they had been represented, but they one and all described the dangers of the river below as stupendous. The _voyageurs_ grumbled, but did not openly rebel. As for the Indians of Mackenzie’s party, they were in open terror; expected at every turn of the river to come upon some of the fearful monsters of which the Slaves or Dog-ribs had warned them, and were only kept from deserting by Mackenzie’s overmastering will. As they approached the mouth of the river, another terror was added--fear of meeting the Eskimos, for Indian and Eskimo were at deadly enmity. Altogether, the plucky explorer had troubles enough. On the second of July he came within sight of the Rocky Mountains, whose glistening summits the Indians called _Manetoe aseniah_, or spirit-stones, and the following day he camped at the foot of a remarkable hill, constantly referred to in the narratives of Sir John Franklin, Richardson, and other later explorers, as the "Rock by the River Side." There is an admirable drawing of the rock, by Kendall, in the narrative of Franklin’s second voyage. A few days later Mackenzie passed the mouth of Bear River, draining that huge reservoir, Great Bear Lake, whose discovery remained for later explorers to accomplish, and about one hundred and twenty-five miles below he came to the Sans Sault Rapids--the fearful waterfall against which the natives had warned him. As a matter of fact it can be safely navigated at almost any season of the year. Another thirty miles brought the explorer to the afterward famous Ramparts of the Mackenzie. Here the banks suddenly contract to a width of five hundred yards, and for several miles the travellers passed through a gigantic tunnel, whose walls of limestone rose majestically on either side to a height of from one hundred and twenty-five to two hundred and fifty feet.