Transactions of the Geological Society, 1st series, vol. 2/Geology of the Coast of Labrador
XX. Notice relative to the Geology of the Coast of Labrador.
By the Rev. Mr. Steinhauer.
THE coast of Labrador is a part of the British territories so little known, and possessing so few inducements to attract the visits of strangers, that every fragment of information concerning it may be esteemed in some degree valuable. This is the only excuse for offering the following observations in their present very imperfect state.
The only English accounts of this country, as yet published, are the memoir of Lieut. (afterwards Sir Roger) Curtis, and Mr. Cartwright's journal. The first-mentioned gentleman reconnoitred the coast from the Straits of Belle-Isle to lat. 58°, 10′, (according to Arrowsmith's chart, 57° 25′,) in the year 1773, by command of Governor Schuldham. His account is inserted in the Philosophical Transactions. The latter person does not appear to have gone farther north than lat. 54°, and his observations refer to little farther than the fishery and peltry trade. At the request of the British government, and particularly of Sir Hugh Palliser, then governor of Newfoundland, the United Brethren made several voyages of discovery to this coast; and in 1772, formed a settlement in lat. 56° 38′, (56° 24′ Arrowsm.) called Nain; and subsequently two others, Okkak and Hopedale, in lat. 58° 43′, and 55° 36′. Hence they have made several excursions, and last year doubled Cape Chudleigh, in lat. 60° 20′, and descended on the opposite or western side of the promontory as far as lat. 58° 36′.
The missionaries, assiduously occupied with the great aim for which they are sent, may be supposed to have but little time for objects of mere science; they have however not been neglectful of the opportunities their stations afforded, but have improved them as far as their abilities allowed. They have kept meteorological tables of the barometrical and thermometrical variations,[1] a tolerably complete flora has been collected; they have from time to time sent specimens of the minerals of the country; and their diaries and verbal accounts furnish some idea at least of the principal mountains on the coast. It is to be regretted that their observations are of such a nature as to throw little light on the geology of the country; even the specimens sent have not always their habitats affixed, or get confounded on board of the vessel. The general aspect of the country is else such as to promise interesting results, and the examination of the different strata is not liable to those obstructions from the enveloping mantle of vegetation and alluvial mould which so often baffle all research in our countries. According to the descriptions of those who have had an opportunity of contemplating this inhospitable region, it consists almost entirely of barren rock, towering in craggy eminences, on which even the hardy lichen in vain endeavours to fix a habitation; for moisture enters the rock with its fibres; the intense cold of winter congeals that moisture, and the summer's thaw precipitates the loosened fragment with its tenant to the foot. These fragments, mouldering into sand, afford in some places support to a few species of pines, and the annual decomposition of their leaves stains this earth to the depth of a few inches with a blackish hue. In other spots where the thawing snow occasions an accumulation of water, sphagna and other mosses form a species of turf, and conceal the barrenness of the land; but every where the plucking up a tuft of vegetation, or removing the withered leaves, discovers either the bare rock or a bright siliceous sand. In several parts of the country the rocks are intersected by chasms running generally in a right line to a considerable distance, as if intended to be the receptacles of future veins; the floor, as I am informed, is composed of a different species of stone from the sides, and generally of a lighter colour; but I could not, from the description, ascertain whether it was calcareous or not. These clefts when covered with snow in the winter, sometimes prove dangerous pitfalls to the unwary wanderer, who does not know how to avoid them by the line of bushes (vaccinia, ledum, &c.) which fringe their margin. Indeed the narrow passages which divide the coast into numberless islands, almost seem to be similar chasms occupied by the sea, few, if any, of these islands being alluvial, but high barren rocks, appearing from the sea like continuous land.
The highest mountains seem to extend along the eastern coast; the names and situations of the principal, known to the missionaries, are
The Nachwak chain, about lat. 59°.
The insulated mountain, Tupperlik, (the tent) lat. 58° 15′.
The Kaumayok chain terminating in the high island of Cape Mugford or Grimmington, lat. 58°.
The high land of Kiglapyed, in lat 57°.
The Mealy mountains laid down on Lane's survey of the coast of Labrador, in lat. 53° 50′, and said to be never free from snow; they have not been visited by the missionaries, who now seldom go far to the south of Hopedale.
With respect to their actual height little can be said with certainty, but as Mount Thoresby, on an island south of Kiglapyed was ascertained by the officers of H.M.S. Medusa and Thalia, to be 2733 feet, and the Kiglapyed is evidently higher, yet inferior to the Kaumayok and Nachwak heights, the latter cannot be assumed at less than 3000 feet. This supposition gains additional probability, from the circumstance that the Kaumayok has been seen by Capt. Frazier,[2] at a distance of upwards of 30 leagues from land. The mountains to the west of Cape Chudleigh are much lower, and, according to the accounts of the missionaries, of a different nature; but wherein the difference consists we are unable to determine.
It would, doubtless, be highly interesting to ascertain the constituent strata of these elevations; but the attention of the missionaries being more directed to mineralogical than geological specimens, and being apt to esteem nothing worth notice, but what, by form or colour attracted notice, we have little more than hints to guide our suppositions.
From the islands near Cape Chudleigh we have received specimens of large-grained pale granite, with garnets. The island of Ammitok (about lat. 59' 20′) is described as consisting almost entirely of a crumbling granite, sometimes mixed with hornblende. The mountains of Nachwak, about Nachwak bay, furnish considerable quantities of lapis ollaris, generally of the grey kind, (of which a specimen is sent) but sometimes of the semi-transparent green variety. The missionaries describe the southern part of this chain, as exhibiting a very singular appearance towards the sea, being composed of alternate layers of black and white rock in a vertical position, which makes the cliffs seem striped; the black strata are about 5 feet in thickness, the white double that breadth. Nulletartok bay, still farther south, and probably near the extremity of the same chain, has been called Slate Bay, from a stratum of slate which appears there a little above high-water mark; from this stratum the travellers write, that an acrid liquid, of a strong sulphurous smell, exudes, which seems to indicate an impregnation with sulphuric acid. Below high-water mark, in the same bay, they noticed a stratum, which they describe as resembling cast iron, with a glossy, somewhat reddish, surface, and extremely hard, (qu. a haematitic iron ore?) The north side of the Kaumayok mountains consists of a white stone, with black or grey veins, resembling statuary marble, but very hard. Of the productions of the Kiglapyed we have no account, but to the south of this chain the district commences, where the Labrador felspar is found. This stone was first distinguished by the late Rev. B. Latrobe,[3] among a number of specimens sent to him; it occurs not only in pebbles on the shore, but in spots in the rocks in the neighbourhood of Nain, and particularly near a lagoon, about 50 or 60 miles inland, in which Nain north river terminates. Its colours darting through the limpid crystal of the lake, and flashing from the cliffs more especially when moistened by a shower of rain, changing continually with every alteration in the position of the boat, are described as almost realizing a scene in fairy land. The same district produces also the Labrador hornblende, (Hyperstène) and the white stone striped with green, which seems to constitute a rock on an island near Nain, and was first noticed by the Rev. C. J. Latrobe, among other fragments, which induced him to cause large fragments to be broken off and brought over.
One of the mountains in the vicinity of Nain, as well as several others in different parts of the coast, exhibits a species of Mam-tor, continually crumbling away and shivering down into the valley below; a splinter of this rock is sent for the inspection of the Society.
The island of Ukusiksalik or freestone island, has derived its name from the quantities of lapis ollaris found there. It is probably the most southern place on the coast where this mineral occurs, as the missionaries, who first visited the Eskimos in Chateau Bay, in the Straits of Belle Isle, were told by them that they procured the stone of which their lamps, pots, &c. were made from this island.
At Hopedale the secondary limestone seems to come in; at least we have received from this place fragments of reddish carbonate of lime, calcareous spar, and schiefer spar. Mr. Latrobe also possesses a madrepore, said to have been found there. It is remarkable that the river abounds in fragments of stone, worn into the most fantastic shapes, in which the imagination without great exertion may trace the rude resemblance of birds, crocodiles, &c. They sometimes form rings six or eight inches in diameter, and three quarters of an inch thick. Their great abundance precludes the possibility of their being the work of art.
With respect to the land, west of Cape Chudleigh, as it has been but once visited, we cannot expect to learn much about it. The mountains of Torngarsuit, (the evil spirit) in lat. 60°, are described as rugged, barren, and black, and containing a huge cavern which the heathen Eskimos fable to be the habitation of the devil. The rocks farther north are light-coloured, but there appear to be no mountains of considerable height on this part of the coast which is called Ungava. On almost every part of it fragments of a red jasper, impregnated with iron, are frequent, and in some places haematites and cubical pyrites. It may be worth remark, that the tides rise here no less than 40 to 50 feet, while they seldom exceed 8 or 10 on the eastern coast. The current sets from west to east round Cape Chudleigh.
The specimens of rocks from Labrador, which Mr. Latrobe has desired me to select for the Society, will enable them to form any further conjectures with respect to the geology of this country far better than I should be able to do it, and I shall esteem myself happy if future opportunities enable me to discover any thing which may be able to throw a more direct light upon the subject.
The specimens marked merely Labrador, are from one or other of the three settlements, consequently found between lat. 55° 30′, and 57° 40′.
- ↑ In Nain the extremities of cold and heat in the year Nov. 1, 1772, to Nov. 1, 1773, were─Jan. 16, 8 h. A.M. 42 under Farenheit's O, and Aug. 2, 2 h. P.M. 86. From Jan. 11 to Jan. 27, the thermometer was never above Fahrenheit's O.
- ↑ The master of the ship annually sent with provisions to the missionaries.
- ↑ President of the Society for the furtherance of the Gospel established by the Brethren.