Narrative of a Second Expedition to the Shores of the Polar Sea Part 16

FOOTNOTES:

[15] Notwithstanding the severity of the weather, we had great difficulty in causing these animals to depart from their usual custom of sleeping in the snow, and in inducing them to occupy the warm houses which were built for them.

[16] I have pleasure in mentioning that, by permission of Government, the pay which was due to Augustus and Ooligbuck, has been delivered to the Directors of the Hudson's Bay Company, who have undertaken to distribute it to them annually, in the way suited to their wants.

[17] I am happy to add, that those men who had been in His Majesty's service before the present Expedition, have been rewarded by promotion.

[18] See page 388.

[19] See Dr. Richardson's opinion in favour of this route, p. 218.

APPENDIX.

TOPOGRAPHICAL AND GEOLOGICAL NOTICES, BY JOHN RICHARDSON, M.D., F.R.S., &c. SURGEON AND NATURALIST TO THE EXPEDITION.

[_Read before the Geological Society._]

A very limited portion of my time could be allotted to geological inquiries. For eight months in the year the ground in the northern parts of America is covered with snow; and during the short summer, the prosecution of the main object of the expedition rendered the slightest delay in our journey unadvisable. The few hours that could be stolen from the necessary halts, for rest and refreshment, were princ.i.p.ally occupied in the collection of objects for the ill.u.s.tration of botany and zoology. It is evident, that an account of the rock formations, drawn up under such circ.u.mstances, cannot be otherwise than very imperfect; but I have been led to publish it from the belief that, in the absence of more precise information, even the slightest notice of the rocks of the extreme northern parts of the American continent would be useful to those employed in developing the structure of the crust of the earth; the more especially, as it is not probable that the same tract of country will soon be trod by an expert geologist. The specimens of rocks I obtained have been deposited in the Museum of the Geological Society, and are referred to in the ensuing pages by the numbers affixed to them. The notices are arranged nearly in the order of the route of the expedition, commencing with Great Bear Lake, where our winter quarters were situated.

GREAT BEAR LAKE.

Great Bear Lake is an extensive sheet of water, of a very irregular shape, being formed by the union of five arms or bays in a common centre. The greatest diameter of the lake, measuring about one hundred and fifty geographical miles, runs from the bottom of Dease Bay, which receives the princ.i.p.al feeding stream, to the bottom of Keith Bay, from whence the Bear Lake River issues, and has a direction from N.E. to S.W.

The transverse diameter has a direction from N.W. by W. to S.E. by E., through Smith and M'Tavish Bays, and is upwards of one hundred and twenty miles in length. M'Vicar Bay, the fifth arm of the lake, is narrower than the others, and being a little curved at its mouth, appears less connected with the main body of water. The light bluish-coloured water of Great Bear Lake is every where transparent, and is particularly clear near some primitive mountains, which exist in M'Tavish Bay. A piece of white rag, let down there, did not disappear until it descended fifteen fathoms. The depth of water, in the centre of the lake was not ascertained; but it is known to be very considerable.

Near the sh.o.r.e, in M'Tavish Bay, forty-five fathoms of line did not reach the bottom. Owing to the barometers supplied to the expedition having been broken in an early period of its progress, the height of the surface of Bear Lake above the Arctic Sea could not be ascertained; but it is, probably, short of two hundred feet.[20] If this supposition comes near the truth, the bottom of M'Tavish Bay is below the level of the sea, and towards the centre of the basin of the lake the depression is probably still greater. The great lakes, Huron, Michigan, and Superior, which discharge their waters into the St. Lawrence, are reported to sink three hundred feet below the level of the ocean; and the Lake of the Mountains, or Chipewyan Lake and Great Slave Lake,[21]

through which the Mackenzie flows, have, it is highly probable, some portions of their beds below the sea level.

In the autumn of 1825, I coasted the western and northern sh.o.r.es of the Great Bear Lake; and in the spring of 1826, travelled on the ice along its eastern and southern arms, leaving no part of its sh.o.r.es unexamined on these two surveys, except the north side of M'Tavish Bay. I did not, however, on these occasions, make excursions inland.

PRIMITIVE ROCKS.--GREAT BEAR LAKE.

At the south-east corner of M'Tavish Bay, primitive rocks form a hilly range which, at the distance of a mile or two from the sh.o.r.e, attains an elevation of eight hundred or one thousand feet. The steep face of the range forms the sh.o.r.e of the lake for fifteen miles, and perhaps further, on a direction from N.W. by W. to S.E. by E., and is prolonged on the latter bearing, at the back of the lower country lying towards Point Leith. The general form of the hills is obtuse-conical, in some instances approaching to dome-shaped. None of them rise much above the others, and the vallies between them are seldom wide or deep. At a distance, some of the ma.s.ses of rock appear round-backed; and in certain points of view, the crest of the ridge seems to consist of mammillary peaks. On a nearer approach, the individual hills are found to be composed of rounded eminences, having summits, generally, of an oblong form, and consisting of smooth, naked rock. Small mural precipices are frequent, and many detached blocks of stone lie beneath them. Between the eminences, there are level spots dest.i.tute of vegetation, and covered with small stones or gravel not much worn. A considerable portion of the gravel is granite or quartz, the debris, perhaps, of the rocks, of which the hills consist; it contains also some pieces of slate, and not a few of quartzose sandstone, neither of which I observed _in situ_. In the course of a walk of two miles over these hills, the only rock I observed was granite, verging in a few places towards gneiss, and generally whitish, with black mica. Sometimes the felspar is brownish-red, and the rock not unfrequently contains disseminated augite? The weathered surface of the stone was every where of a brick-red colour. In many spots the rocks split into such thin slaty looking tables that they have the appearance of being stratified. The slaty ma.s.ses are, generally, vertical; but in one hill they were observed dipping 80 degrees to the south-east. The direction of the tabular ma.s.ses is mostly across the oblong summits of the hills. The appearances of stratification were not observed to extend through a whole hill, and seemed, in fact, to be confined to the more decomposable granites; but the naked rocks are every where traversed by smooth fissures. The blocks, which lie under the cliffs, have sometimes a tabular form, but more generally come nearer to a cube or rhomboid, and present one or two very even faces. Few veins were noticed. In the more sheltered vallies, some clumps of white or black spruce trees occur; but the hills are barren.

The point of land which lies between M'Tavish and M'Vicar Bays has low sh.o.r.es; but five or six miles inland, an even-backed ridge rises gradually to the height of three or four hundred feet, and abuts obliquely against the primitive hills. I did not visit this ridge, and the snow prevented me from seeing any flat beds of rocks, if such exist on the sh.o.r.e. On one point, however, near the north end of Dease Bay, many large angular blocks of whitish dolomite were piled up, and I have little doubt of the rock existing _in situ_ in that immediate neighbourhood.

M'Tavish Bay is forty miles long, and twenty wide, and its depth of water, near the eastern sh.o.r.e, exceeds forty-five fathoms. Some shoals of boulders skirt the coast near Point Leith. M'Vicar Bay is about seventy miles long, and from eight to twelve wide; and at the "fishery,"

in a narrow part, not far from its bottom, its depth of water, two miles from the sh.o.r.e, is twelve fathoms. Dease Bay is equal to M'Tavish Bay in extent, and opens to the S.W. into the body of the lake. The high lands at the N.E. end, or bottom of this bay, have an even outline, and appear to attain an elevation of eight or nine hundred feet, at the distance of six or seven miles from the sh.o.r.e. Near its east side lie the lofty islands of Narrakazzae which rise seven hundred feet above the lake.

Dease River, the princ.i.p.al feeder of the lake, falls into the bottom of Dease Bay. It is two hundred yards wide, and from one to three fathoms deep near its mouth. A few miles up this river a formation of soft red sandstone occurs, which will be noticed hereafter.

LIMESTONE.--GREAT BEAR LAKE.

[Sidenote: 228*] At the mouth of Dease river there are hills five or six hundred feet high, composed princ.i.p.ally, or entirely, of dolomite in horizontal strata. Some of the beds consist of a thick-slaty, fine-grained dolomite, containing dispersed scales of mica, which is most abundant on the surfaces of the slates. [Sidenote: 228] Most of the beds, however, consist of a thin-slaty, dull, purplish dolomite, traversed by veins of calc-spar. The structure of this rock is compact, approaching to fine granular; and some of the beds have what quarry-men term "clay-facings," that is, they are encrusted with a thin film of indurated clay.

Greenstone slate? occurs in horizontal beds on the north sh.o.r.e, eight or nine miles to the westward of Dease River: and at Limestone Point,[22]

about twenty miles from the river, a small range of hills terminates on the borders of the lake, in shelving, broken cliffs, about two hundred feet high. These cliffs consist chiefly of nearly compact light-coloured dolomite, interstratified with greenstone, and a brownish-red limestone, such as occurs in the hills at the mouth of the Dease River. In contact with the greenstone, there is a bed of talcose limestone, having a curved, slaty structure; most of the beds of dolomite are hard, and pa.s.s into chert.

ALUMINOUS SHALE.--GREAT BEAR LAKE.

The north sh.o.r.e of Bear Lake is low, and is skirted by many shoals, formed by boulders of limestone. No rocks, _in situ_, are exposed between Limestone Point and the Scented Gra.s.s Hill, a remarkable promontory, which separates Smith and Keith bays. Its height above the lake is betwixt eight and nine hundred feet, and in form and alt.i.tude it corresponds with the Great Bear Mountain, which, lying opposite to it, separates M'Vicar and Keith bays. I did not ascend either of these hills; but cliffs, corresponding in character to those of the aluminous shale-banks at Whitby, flank their bases; and the same formation probably extends along the north sh.o.r.e of Keith Bay, and some way down Bear Lake River. The ground skirting the Scented Gra.s.s and Great Bear Mountains is much broken, and consists of small, rounded and steep eminences, separated by narrow vallies and small lakes. Several shelving cliffs, about one hundred feet high, and some miles in extent are washed by Bear Lake. [Sidenote: 251] They consist of slate-clay and shale, more or less bituminous, and the dip of the strata is in several places to the N.W. by N. [Sidenotes: 244, 246, 247] At the foot of the Scented Gra.s.s Hill a rivulet has made a section to the depth of one hundred feet, and here the shaly beds are interstratified with thin layers of blackish-brown, earthy-looking swinestone, containing selenite and pyrites. Globular concretions of the same stone, and of a poor clay iron-stone, also occur in beds in the shale. [Sidenotes: 249, 250, 248]

The surfaces of the slates were covered with an efflorescence of alum and sulphur. Many crystals of sulphate of iron lie at the bottom of the cliff, and several layers of plumose alum, half an inch thick, occur in the strata. At the base of Great Bear Mountain, the bituminous shale is interstratified with slate-clay, and I found imbedded in the former a single piece of brown coal, in which the fibrous structure of wood is apparent. Sections of slate-clay banks, and more rarely of bituminous shale, occur in several places on the north sh.o.r.e of Keith Bay. In one place, about seven or eight miles from Bear Lake River, a bed of plastic and bituminous clay occurs, and in another, near Fort Franklin, there is a deposit of an earthy coal, which possesses the characters of _black chalk_.

It is probable that a magnesian limestone underlies this formation of bituminous shale. I have already mentioned the beds of dolomite, which are exposed on the north side of Bear Lake, and similar beds occur to the southward of the Great Bear Mountain, forming cliffs on the sh.o.r.es of M'Vicar Bay. At Manito Point, on the west side of the isthmus that connects Great Bear Mountain to the main sh.o.r.e, a low ridge of limestone rocks terminates on the borders of the lake, forming some bold cliffs and a remarkable cave. The stone has a gray colour and bituminous smell, and contains much interspersed calc-spar. The strata dip to the north-west.

VICINITY OF FORT FRANKLIN, GREAT BEAR LAKE.

Fort Franklin stands on the northern sh.o.r.e of Keith Bay, about four miles from Bear Lake River, upon a small terrace, which is elevated twenty-five or thirty feet above the lake. The bay, contracting towards the river, is about four miles wide opposite to the fort, and the depth of water there does not exceed four fathoms. Farther from the river, the east and west sh.o.r.es of Keith Bay recede to the distance of thirty miles from each other, and the depth of water in the centre of the channel greatly increases. The bottom of this bay, wherever it could be distinguished, was observed to be sandy, and thickly strewed with round boulders[23] of various primitive rocks of large size, which were particularly abundant near the river, and with large square blocks of limestone, most plentiful near the cape formed by the Scented Gra.s.s Hill. In the small bay between the fort and the river, shoals are formed by acc.u.mulations of boulders, and the sh.o.r.es are thickly strewed with them. [Sidenote: 261 to 308] Many of these travelled blocks consist of flesh-red granite, having only a small quant.i.ty of black mica, exactly resembling the primitive rocks seen in M'Tavish Bay, but noticed no where else near the lake. Boulders of the same description occur in shoals at the mouth of M'Tavish Bay, and on the sh.o.r.es which skirt the Scented Gra.s.s Hill which faces that bay, to all which places they may have been brought from the parent rock, by a current flowing from the east. On the northern sh.o.r.e of Bear Lake the great majority of the boulders consists of limestone. [Sidenote: 266 282] Two varieties of granite, which occur amongst the boulders, were recognised as being abundant rocks at Fort Enterprise, which is situated about one hundred and seventy miles south-east from M'Tavish Bay. Some of the boulders were of a peculiar-looking porphyry exactly resembling that which occurs in the height of land betwixt the Coppermine River and Dease Bay; several of sandstone and conglomerate, which probably came from the same quarter; of greenstone, perhaps, from the Copper Mountains, and of limestone from the northern sh.o.r.es of the lake, and from the isthmus of the Great Bear Mountain; all these places lying to the eastward or north-east.

The soil in the immediate vicinity of Fort Franklin is sandy, or gravelly, and covers, to the depth of one or two feet, a bed of clay of unknown thickness. Gravel taken from a spot thirty feet above the present high-water level of the lake, and out of the reach of any stream or torrent, contained rounded pebbles of granite, of greenstone, of quartz rock, of lydian stone, and of various sandstones, of which some were spotted, and others presented zones of different colours. These sandstones form a considerable portion of the gravel.[24]

The clay which lies under the soil is of a bluish-gray colour, and is plastic but not very tenacious. It is more or less mixed with gravel.

During the greater part of the year it is firmly frozen; the thaw in the two seasons we remained there never penetrating more than twenty-one inches from the surface of the earth. In spots where the sandy soil is wanting, the clay is covered a foot deep, or more, by mosses, mostly _bryum pal.u.s.tre_, and some marsh _hypna_ and _dicrana_, in a living state, for they seem to be converted very slowly into peat in this climate.

The ground rises gradually behind the fort, until it attains, at the distance of half a mile from the lake, the height of two hundred feet, forming, when viewed from the southward, an even ridge, running nearly east and west--which ridge is, in fact, the high bank of the lake, as it corresponds in height with the summit level of the banks of Bear Lake River, and of the southern sh.o.r.e of Keith Bay. The country extending to the northward, from the top of the bank, is nearly level, or has a very gentle ascent for about five miles, when a more abrupt ridge rises to perhaps three hundred or four hundred feet above the lake. The view from the summit of this second eminence is very extensive, the whole country as far as the eye can reach appearing to be a level, from which several narrow precipitous ridges of limestone arise. But, although the country around these ridges appears from a distance to be level, or very slightly undulated, yet it abounds in small eminences and steep-sided vallies of various shapes, some being rounded and basin-shaped, others long and narrow. Lakes and swamps are here so numerous, that the country, for at least sixty miles to the northward, is impa.s.sable in summer, even to the natives. There are many mounds of sand and gravel, and fragments of sandstone are frequent; but having travelled in this direction only in winter, when the ground was covered to the depth of upwards of three feet with snow, I had not an opportunity of examining its geological structure. White spruces cover the drier spots; larches, black spruces, and willows abound in moist places; the sandy hillocks are clothed with aspens, and the sides of the vallies support some canoe birches, with a thick undergrowth of dwarf birches, alders, and rose-bushes. The eminence from whence the view just described was obtained, appears like a ridge only in approaching it from the lake, for it rises very little above the general level of the country behind it.

It has a direction from N.W. by N. to S.E. by S., and terminates about eight miles to the eastward of the fort, in a small bluff point on the sh.o.r.es of the lake and there the strata consist of slate-clay slightly bituminous. The banks immediately behind the fort also exhibit, in their ravines, a bluish slate-clay.

The land on the south side, or bottom, of Keith Bay, presents a nearly similar aspect to that just described, rising, on the borders of the lake, to the height of one hundred and fifty feet, and then running back to a great distance nearly level. It may be characterized as full of hollows, narrow vallies, ravines, and lakes; but it is not hilly, although it is traversed by ridges of limestone, which rise like walls through the flat country. The nearest of these ridges terminates on the borders of the lake at the _Manito Point_, (noticed in page vii.) It may be proper to remark here, that, in addition to the limestone ridges visible from Fort Franklin, or from the heights behind it, the summit of Clark Hill, bearing south, and forming part of a ridge about fifty miles distant, was distinctly seen. This hill lies behind Old Fort Norman on the Mackenzie, and has more the outline of a granitic rock, although some of the peaks which skirt it have the serrated crests which the limestone ridges in this quarter show. It was guessed to be 1500 feet high above the Mackenzie.

This sketch of the general features of the country about Fort Franklin being premised, the ensuing geological notices follow in the order of the route of the Expedition.

BEAR LAKE RIVER--SANDSTONE, LIMESTONE.

Bear Lake River is about seventy miles long, from its origin in the lake till it falls into the Mackenzie, and throughout its whole length, its breadth is never less than one hundred and fifty yards, except at the _Rapid_, a remarkable place, about the middle of its course. It is from one to three fathoms deep, and very rapid, its velocity being estimated at six miles in the hour. Its waters are clear as they issue from the lake, but several branches of considerable size bring down muddy water, particularly one which flows from the north, and falls in below the rapid.

Above the rapid, the valley of the river is very narrow, the banks every where sloping steeply from the level of the country. Their summit line, which is nearly straight, is about one hundred and fifty feet above the bed of the river. In some places they have an even face elevated at an angle of about forty-five degrees, and they are not unfrequently cut by ravines into pretty regular figures, resembling hay-ricks, or the parapet of a fort, the ravines representing the embrasures. Sections made by the river presented generally sand or clay; the sand probably proceeding from the disintegration of a friable, gray sandstone, which showed itself occasionally in a more solid form. The rapidity of our voyage, however, afforded us little opportunity of searching for the solid strata which are generally hid by the debris of the bank. About twelve miles above the rapid, a small-grained, friable sandstone, of a yellowish gray colour, and irregular earthy fracture, is a.s.sociated with beds of bluish-gray slate-clay. These beds consist of concretions of various sizes and irregular shapes, but which may be said to approach in general to a depressed orbicular form; their surfaces are coloured purplish-brown by iron, and studded with crystals of sulphate of lime.

This slate-clay contains many small round grains of quartz, and is exactly similar to that which occurs at the rapid, and which will be afterwards noticed. In other places the banks are covered by the debris of a slate-clay slightly bituminous, resembling wacke in its mode of disintegrating.

The _Rapid_ is caused by the river struggling through a chasm bounded by two perpendicular walls of sandstone, over an uneven bed of the same material. On escaping from this narrow pa.s.sage, it winds round the end of a lofty cliff of limestone, which forms part of a ridge that is continued through the country on both sides of the river.

Viewed from the summit of this ridge, which rises about eight hundred feet above the river, the country towards Bear Lake appears level. The view down the river presents also a plain country, bounded on the Mackenzie by another limestone ridge, which, unless the eye was deceived by the distance, gradually inclined to the one at the rapid, and appeared, by joining it to the northward, to form a great basin. These ridges are also prolonged to the southward. The plain is covered with wood, intersected by chains of lakes, and seemed to lie rather below the summit level of the banks of Bear Lake River. It is only comparatively, that the country deserves the name of plain, for its surface is much varied by depressions, ravines, and small eminences, that do not, however, destroy the general level appearance when seen from a distance.

The view from the hill is terminated, to the westward, by the distant chain of the Rocky Mountains, running nearly N.W. by N. A little below the rapid, a small stream from the southward flows into the Bear Lake River, near whose sources the Indians procure an excellent common salt, which is deposited from the springs by spontaneous evaporation.

The walls of the rapid are about three miles long, and 120 feet high.

[Sidenote: 25] They are composed of horizontal beds, the lower of which consist of an earthy-looking stone, intermediate between slate-clay and sandstone, having interiorly a dull yellowish-gray colour. Concretions, with smooth surfaces, about the thickness of a swan's quill, pa.s.s perpendicularly through the beds like pins, are prolonged beyond the partings, and bear some resemblance to portions of the roots or branches of a tree. The seam surfaces are very uneven. [Sidenote: 18] These beds are parted by thin, slaty layers, of a stone similar in appearance, but rather harder, and containing many interspersed scales of mica, and also some minute portions of carbonaceous matter in the form of lignite.

[Sidenotes: 19, 1827] The thin layers contain impressions of ferns, and from the debris at the bottom of the cliff I gathered impressions of the bark of a tree (lepidodendron) and some ammonites in a brown iron-shot sandstone.[25] [Sidenote: 18, 20, 21, 22, 23, 24, 26, 27, 28] The upper beds are composed of a fine grained, quartzose, gray sandstone, having an earthy basis, and occasionally interspersed carbonaceous matter. Some of the beds are a foot and a half thick, and have sufficient tenacity to be fitted for making grindstones; most of the sandstone is, however, rather friable. Near the summit there is interposed a bed of fine-grained dolomite, and a friable sandstone, which forms the crest of the cliff, and exhibits in its weathering battlement-shaped projections and pinnacles. [Sidenote: 29] Covering this sandstone, but not quite to the margin of the cliff, there is a layer of slaty limestone, having a bluish or blackish-gray colour, a dull fracture, and rather compact structure. [Sidenote: 30] In the lower beds of the cliff there are some globular and disk-shaped concretions, of an indurated iron-shot slate-clay, or poor clay-iron-stone, containing pyrites. They vary in magnitude from six inches to a foot and a half in diameter, and appear to be formed of concentric layers, which are rendered apparent by the weathering of the stone. The sandstones and shales of the rapid have a strong resemblance in appearance to those of the coal measures; but pitch-coal was not detected at this place. Several distinct concretions of indurated slate-clay, a.s.suming the appearance termed _cone in cone_, were picked up among the boulders on the banks of Bear Lake River, some way below the rapid, but they were not traced to their parent beds. They effervesce with acids.

Between the walls of the rapid and the limestone ridge there is a piece of meadow-ground, having a soft, clayey soil, in which, near the base of the hill, a small rivulet flows to join the river. The bed of this rivulet presents acc.u.mulations of boulders of large size, arranged so as to form two terraces, the upper of which is considerably above the highest level either of the rivulet, or of Bear Lake River. The boulders consist of varieties of granite, gneiss, mica-slate with garnets, greenstone and porphyry. [Sidenote: 50] One of the porphyries is a beautiful stone, composed of hyacinth-red felspar, and irregular crystals of milky quartz, with a few specks of a dark green mineral, and very much resembles a rock which is not uncommon in the gneiss districts about Fort Enterprize. [Sidenotes: 45, 47, 50, 51, 49] Many of the boulders consist of conglomerates and sandstones that strongly resemble those of the old red sandstone formation, which forms the height of land between Dease Bay and Coppermine rivers. Also some flinty slates, mixed, in thin layers, with compact, yellowish limestone, and some pebbles of jasper interleaved with flinty slate.

The limestone ridge below the rapid stands on a narrow base, whose transverse diameter does not exceed a quarter of a mile. Its summits are generally conical, but very rugged and craggy; the highest peak I had an opportunity of visiting is about a mile from Bear Lake River, and it has been already stated to be estimated at eight hundred feet above that stream, or nine hundred and fifty above the sea. The general direction of the ridge is from S.E. by S. to N.W. by N., or nearly parallel to the great Rocky Mountain chain, and to the smaller ridges betwixt it and that chain. Its prolongation through the flat surrounding strata, to the southward of Bear Lake River, can be traced for at least forty miles, and it is visible at nearly an equal distance, as it runs through the still more level country to the northward; but here, as has been already said, it appears to incline towards the similar ridge which is cut by the Mackenzie, at the mouth of the Bear Lake River, and is about twenty-five miles to the W.S.W., in a direct line. That part of the ridge which I had an opportunity of visiting, consisted entirely of limestone, generally in thick beds. Its stratification was not very evident, and in my very cursory examination the general dip was not clearly ascertained. A precipitous cliff, four hundred feet high, facing the S.E., and washed by the Bear Lake River, presents strata, inclined to the S.W. at an angle of 45 degrees, which may be perhaps considered as the general dip; for the ridge on that side slopes down to the surrounding country at an angle of about 30 degrees or 40 degrees, while on the N.E. side it presents lofty precipices formed by the cropping out of the strata. [Sidenote: 39, 34] Many of the beds in this hill consisted of a blackish-gray fine grained limestone, intersected by veins of calc-spar; [Sidenotes: 40; 35, 36; 42, 43, 44] but several layers of gray and dark coloured dolomites, and some of a yellowish-gray _rauchwacke_, were interstratified with them, and the upper parts of the precipitous cliff, [Sidenote: 35, 36] and also of the highest peak, consisted of a calcareous breccia, containing rounded pieces of brown limestone, and angular fragments of chert; and the faces of some cliffs, on the N.E. side of the hill, were incrusted with a fine crystalline gypsum to the depth of from one to two feet.[26]

The banks of Bear Lake River below the rapid have a more gentle declivity than those above it, and they occasionally recede from the stream, so as to leave a gra.s.sy slope varying from a few yards to half a mile in breadth. The sections of these banks by torrents present only sand or clay; and the hollows of the ravines are lined with boulders princ.i.p.ally of primitive rocks. No stone was observed _in situ_ from the rapid until we came to the junction of the river with the Mackenzie.