The journey northward was pursued with very varying fortunes. The ice was exceedingly bad, and when the ships were not actually beset in it, they were occupied in charging their way through it. Little by little, however, they made their way up the channel, caching large stores of provisions as they went, among the chief being a depot of 3600 rations on the Carey Islands, another depot of the same size at Cape Hawks, and one of 1000 rations at Cape Lincoln. But ice was not the only difficulty with which Nares had to contend, for Hayes’ chart was a source of perpetual annoyance to him, and a great part of his time was spent in correcting its errors. Cape Frazer was placed eight miles and Scoresby Bay twenty miles too far north, and the rest of the western coast was so badly delineated that Nares pathetically remarked that it was often difficult to know exactly where he was. Hugging the western shore and taking advantage of every channel that opened near the ship, he succeeded in reaching Lady Franklin Bay, on the other side of which he found a land-locked inlet; this he named Discovery Harbour, and in it he decided to leave his companion ship while he himself pushed on in the _Alert_. As he ascended the strait he observed that the character of the ice changed rapidly. Off Cape Sabine the biggest floes were only eight or ten feet thick; off Cape Fraser their thickness increased to twenty feet, and the ice was obviously older, “but,” he says, “up to the present time, when the main pack consisted entirely of heavy ice, I had failed to observe that, instead of approaching a region favoured with open water and a warm climate, we were gradually nearing a sea where the ice was of a totally different formation to what we had ever before experienced, that few Arctic navigators had met, and only one battled with successfully; that in reality we must be approaching the same sea which gives birth to the heavy ice met with off the coast of America by Collinson and M’Clure, and which the latter in 1851 succeeded in navigating through in a sailing vessel for upwards of 100 miles, ... which Sir Edward Parry met with in the same channel in 1820, ... which, passing onwards to the eastward from Melville Strait down M’Clintock Channel, beset, and never afterwards released, the _Erebus_ and _Terror_ under Sir John Franklin and Captain Crozier; and which, intermixed with light Spitzbergen ice, is constantly streaming to the southward along the eastern shore of Greenland, and there destroyed the _Hansa_ of the last German Arctic expedition.” In other words, Nares was in the middle of the ice formed in the Polar Sea, now known as Palæocrystic, and was the first man really to understand its character.