Crossing Green River and following up Ham's Fork, Frémont reached the valley of Bear River, the principal tributary of Great Salt Lake, which was filled with emigrants travelling to the lower Columbia River. Frémont expressed his surprise at the confidence and daring of the emigrants as he met in one place "a family of two men and women and several children travelling alone through such a country so remote from civilization." Turning south from this point and quitting the travelled road Frémont visited the Great Salt Lake, of which he says: "Hitherto this lake had been seen only by trappers, who were wandering through the country in search of new beaver streams, caring very little for geography; its lands had never been visited, and none were to be found who had entirely made the circuit of its shores, and no instrumental observations or geographical survey of any description had ever been made anywhere in the neighboring region. It was generally supposed that the lake had no visible outlet, but among the trappers, including those in my own camp, were many who believed that somewhere on its surface was a terrible whirlpool, through which its waters found their way to the ocean by some subterranean communication." The lake was eventually reached from the lower part of Bear River in an india-rubber canoe, by means of which Frémont also landed on a mountainous island near the centre of the lake, where from an elevation of eight hundred feet he was able to determine with considerable accuracy the contours and extent of this remarkable body of water. Instead of a tangled wilderness of shrubbery teeming with an abundance of game, as the party expected, the island proved to be broken, rocky land, some twelve miles in circumference, on which there was neither water nor trees; a few saline shrubs and other hardy plants formed the only vegetation. The lake is described as being enclosed in a basin of rocky mountains, which sometimes leave grassy fields and extensive bottoms between them and the shore, while in other places they come directly down to the water in bold and precipitous bluffs. He speaks of the water of the lake being at a low stage and the probabilities that the marshes and low ground are overflowed in the season of high water. Frémont says that "we felt pleasure in knowing that we were the first who in the traditional annals of the country had visited the island and broke with joyful sounds the long solitude." But in view of the dissipation of his dream of fertility he named it Disappointment Island.