CHAP. V. PYROGENOUS ROCKS. -RATE OF THE CURRENT OF SLAVE RIVER. - SALT RIVER AND SPRINGS. -GEESE.-GREAT SLAVE LAKE. -DOMESTIC CATTLE.- DEADMAN'S ISLANDS. ALLUVIAL LIGNITE BEDS. HORN MOUN MACKEN TAIN. -HAY RIVER. No primitive rocks were seen on the route down the Mackenzie, on this voyage, after leaving the Portage of the Drowned; but in 1820, when we crossed Great Slave Lake, near the 113th meridian, we traced the western boundary of these rocks, from near the mouth of Slave River, northwards by the Rein-deer Islands to the north side of the lake, and continued to travel within their limits up to Point Lake in the 66th parallel. The western edge of the formation was afterwards found at the northeast and eastern arms of Great Bear Lake. The district intervening between the granite at the Portage of the Drowned and the Salt River is flat, with sandy terraces and slopes rising from the river to the height of from twenty to eighty feet, there being in some places two in others three or more such terraces, while in others the river has made a section of the sandy deposit, and formed a high and steep cliff. The valley of the river, deflected to the westward by the rocks of the portages, passes here through the more level (upper?) silurian strata. At Gravel Point (Pointe de Gravoir), ten miles from the portages, a bed of concretionary or brecciated limestone protrudes from under a sand-bank forty feet high, and two miles higher up a cliff of cream-coloured and brownish limestone stands on the right bank. The country on both sides of the river there appears to be a plain, which has a general level of about fifty feet above the bed of the stream. Just before arriving off the mouth of Salt River, we picked up one of the boat's lockers containing the anchor, which had been carried away fifteen. miles higher up nearly eight hours before, so that it drifted about two miles an hour, including the time it might have been detained in eddies. In 1820, I ascended the very tortuous Salt River, for twenty miles, for the purpose of visiting the salt springs, which give it its name. Seven or eight copious springs issue from the base of a long even ridge, some hundreds of feet high, and, spreading their waters over a clayey plain, deposit much pure common salt in large cubical crystals. The mother water, flowing off in small rivulets into the Salt River, communicates to it a very bitter taste; but before the united streams join the Slave River, the accession of various fresh-water rivulets dilutes the water so much that it remains only slightly brackish. A few slabs of greyish compact gypsum protrude from the side of the ridge above mentioned; and a pure white gypsum is said to be found at Peace Point on Peace River, distant about sixty or seventy miles in a south-south-west direction, whence we may conjecture that this formation extends so far. From the circumstance that the few fossils gathered from the limestone on Slave River are silurian, I venture to conjecture that these springs may belong to the Onondago salt group of the Helderberg division of the New York system. The Athabasca and Mackenzie River districts are supplied from hence with abundance of good salt. We obtained some bags of this useful article from Beaulieu, who was guide and hunter to Sir John Franklin on his second overland journey, and who has built a house at the mouth of Salt River. This is a well chosen locality for his residence: his sons procure abundance of deer and bison meat on the salt plains, which these animals frequent in numbers, from their predilection for that mineral; and Slave River yields plenty of good fish at certain seasons. is the most southern locality to which the Inconnu It or Salmo Mackenzii comes, on this side of the Rocky Mountains, as it is unable to ascend the cascades in the Slave River. The Coregoni are the staple fish of the lakes here, as they are elsewhere throughout the country; and there are also pike, burbot, and excellent trout. A limestone cave in the neighbourhood, which was too distant for us to visit, supplies Beaulieu with ice all the summer, and he gave us a lump to cool water for drinking, which was extremely grateful. The ammunition and tobacco with which I repaid these civilities were no less acceptable to him. Indeed, I believe that he turns his residence on the boat-route to good account, as few parties pass without giving him a call. After a short halt, we resumed our voyage until 7 P. M., when we landed to cook supper, after which we re-embarked to eat it; and, having lashed the boats together, drifted down the stream all night, one man being appointed to steer. July 16th. Though we lay down in the best manner we could in the boats during the night, the continuous assaults of the moschetoes deprived every one of rest, and rendered us all so feverish, that we were glad when daybreak called the crews to the oars, and the boats acquired motion through the water, by which we obtained some relief. The sandy banks of the river show sections in many places upwards of twenty feet high; and, in almost all, the sand is distinctly stratified; the layers being of different colours, and often having clayey or loamy seams interposed. The whole of the banks, from Salt River downwards to Slave Lake, appear to be alluvial; and many small lakes existing behind them communicate with the river by narrow channels. In ordinary seasons at this date, vast numbers of Canada geese moult in the district, and are followed by their young brood not yet fully fledged, which fall a ready prey to the natives or voyagers descending the river. In 1825 I could have filled a boat with these delicate young birds. This year, owing to the high waters, the greater part of the broods had retreated to the lakes, where grass could be more easily procured, and we obtained only a few. The natives observe, that, besides the old birds which rear young, and moult when their offspring are obtaining their plumage, there are a considerable number who do not breed, but keep in small bands, and are called "barren geese." Of these we saw some flocks; but they were not easily approached without a greater loss of time than we could spare. We kept at the oars all day, except when we landed to breakfast, or to cook supper, and, after sunset, resumed the plan of drifting, with very little |