« PreviousContinue »
Scotia, which support the opinions, and correspond with the discoveries of distinguised naturalists in Europe, but more especially to arouse the attention of the inhabitants of the Province, to a due estimation of the advantages they possess, and the resources within their reach. He has therefore, while using such scientific terms and following such a systematic arrangement, as will render his facts plain and precise to those learned in the subjects discussed, written in a manner that will be easily understood by the general reader, to whom the work may be recommended as a good manual. He first gives a succinct Introduction to the study of Geology and Mineralogy. He next offers his "Remarks" regarding Nova Scotia, under these heads. He confesses, however, that the country presents many difficulties to the naturalist, partly because immense tracts of it cannot be traversed on account of its dense forests and inaccessible mountains. Neither have any excavations been made in the Province, except such as are confined to the raising of coal. Cultivation and improvements are yet in their infancy; and, indeed, the facilities for obtaining geological information are confined to the shore, and those places "where the removal of the earth for making roads, has uncovered the rocks which lie beneath."
But there are some advantages also offered to the inquirer in the same region, which are very clearly stated, and which, to such an enthusiast, as our author seems to be in the pursuits in question, in a great measure compensate the disadvantages above referred to.
"Almost surrounded by the sea, Nova Scotia does indeed upon her shores, not only offer the most majestic and beautiful scenery, but affords an opportunity to any enquirer to examine immense precipices and strata of rocks, from which some just inferences may be drawn, in regard to the internal formations of the country. But in general the shores only give a knowledge of the circumference, a short distance from which in some places, other kinds of rocks are deposited. And it should be considered, that every section of the country upon the border of the sea, is very superficial, extending only from the soil to the lowest level of the water. Much information may however be obtained by examining the banks of rivers, deep ravines, and the tops of the highest mountains; although such examinations are not always attended with safety, and are never made without great labour. From these circumstances, it will not be supposed, that a perfect geological description of the country can be given, until time and cultivation shall have removed the obstacles that now lie in the way.
"It should nevertheless be observed, that numerous as the difficulties in the prosecution of geological enquiries may appear in Nova Scotia, there are some circumstances connected with the rocks themselves, which are favourable to their examination, and of much importance in the discovery of useful quarries and mines. These favourable circumstances arise from the highly inclined, and in some situations the almost vertical position of the strata of different classes of rocks. For if the different layers of each
class of the secondary rocks had been horizontal, or remained in that position in which it is supposed they were originally deposited, it would have been impossible, without making deep excavations, to have arrived at any knowledge of the lower classes, now in many places so thrown out of their original level, by the elevation of immense ridges, that extensive ranges are exposed, and may be examined without the labour of removing even the earth from the surface. An instance of this kind is exhibited in the clay slate of the Horton Mountains. The slate is an older formation than the new Red Sandstone, that would have covered it had it not been turned up, so that the sandstone leans against its north side, in contact with its strata.
"Again, it should be observed, that in consequence of the rapid currents upon the coasts of this province, and the exposed situation of the country to the sea, added to the advantages gained by the great height the tide rises in the Bay of Fundy, an excellent opportunity is afforded the mineralogist, to obtain those interesting minerals with which the country abounds. The effects of a turbulent sea, frost, and the action of the atmosphere, produce such destructive results upon the solid materials, thrown up as barriers against the encroachments of the ocean, that every succeeding season opens a new field to those interested in the discovery and collection of minerals."
In pursuing his inquiries into the formations of Nova Scotia, the author divides the province into four distinct Geological Districts; for, speaking generally, he says, that there are lines which separate each division with remarkable definiteness. He accordingly treats first of what he calls the Primary District, in which the Primary rocks are most abundant. The second is the Clay Slate District. The third the Red Sandstone District, including the Coal Fields. And lastly, the Trap District, the rocks of which rest upon the Red Sandstone. It is interesting to hear that these different formations of Nova Scotia correspond with those of the United States-extending in both countries from north-east to south-west -nearly parallel to the Atlantic coast, having the transition and secondary rocks placed to the northward and westward of the primary formations. But as such notices and particulars as these, and the general contents of the volume, cannot prove attractive to the majority of our readers, we shall content ourselves, after having thus pointed out its scope and subjects, with a few extracts, selecting some of those that are the most curious to the multitude. We first look into the Primary District.
"The rocks in the vicinity of the town of Halifax, and the surrounding country, are in general Primary. The granite generally appears on the summits of the hills, having the clay slate and quartz rock alternating in the valleys. The granite of the County of Halifax contains a smaller quantity of mica than is seen in that rock in other parts of the country. Its granular fragments are so intimately united, that they form hard and compact rock, which is seldom decomposed by the action of the weather, and therefore affords no fertility to the soil. Near the town there are two large VOL. III. (1837). No. III.
granitic boulders, so placed as to form rocking stones. They may be rolled from side to side on their bases by slight mechanical pressure, and form places of resort for the curious. One of these natural curiosities has been described by J. Leander Starr, Esq., who, with his usual neatness of style, says.-The rock stands upon a broad flat stone, the surface of which is quite level with the ground, and it is rocked to and fro by the aid of a short wooden lever. Any stick found lying near the spot is picked up for that purpose, and it may thus be set in active motion even by a child. Although very difficult to climb to its summit, I succeeded in doing so, and when my friend plied the lever I sensibly felt its rocking motion as I walked about upon its surface. I examined it very minutely, and discovered the vast body to move upon a pivot of twelve by six inches, situate about the centre, and a slight rest at the north end. The quality of the rock is granite, but apparently somewhat porous.' This stone is twenty feet long, fourteen feet wide, and nine feet thick. It contains two thousand five hundred and twenty solid feet, and will weigh upwards of sixty tons.
"Pliny says, that at Harpasa, a town of Asia, there was a rock of such a wonderful nature, that if touched with the finger it would shake, but could not be moved from its place by the whole force of the body. Several other rocks of this kind have been mentioned by the ancients. Some have supposed that rocking stones, or Logan stones, as they have been called, were monuments erected by the Druids, who pretended that they performed miracles by moving them by gentle means. It is not probable, however, that those singular rocks in Nova Scotia were thus placed to mislead the aborigines of the country, or to deceive the inhabitants of a more enlightened age. These blocks of granite in Nova Scotia were evidently detached and accidentally lodged in their present uneasy situations, by a volcanic eruption, or some violent force, which has acted upon all the rocks in their neighbourhood, and produced that disturbance now so manifest."
Professor Buckland has noticed the irregular blocks of granite in Nova Scotia, in vindicating the doctrines of the flood, which, as in other parts of our globe, where similar phenomena are discovered, show that since they are now lodged upon the soil, they must have been transported from primary situations by some propelling force, unknown to us, such as an overwhelming deluge.
In the Clay Slate District, and near to Clements, we are told by the author, that there is an immense bed of iron ore at the surface of the earth, and situated in a part of the country which at present abounds in fuel. The thickness and quality of this bed, he says, would supply all the inhabitants of America for ages. What is very remarkable, imbedded in the ore and the slate with which it is in contact, the remains and impressions of marine animals are plentiful. In reference to this fact, the following observations are used :
"To support the arguments in favour of the aqueous origin of the iron ore of the South Mountains, it will be immediately observed, that the marine fossil shells contained in it are almost sufficient to demonstrate the fact.
"From whence came these shells; and by what mighty convulsions and changes in this globe have their inmates been deprived of life, and incarcerated in hard, compact, and unyielding rocks? By what momentous and violent catastrophe have they been forced from the bottom of the ocean, (where they were evidently at some former period placed,) to the height of several hundred feet above the level of the present sea, and even to the tops of the highest mountains? It is not an uncommon circumstance in Nova Scotia to see the honest farmer ploughing up the ground once inhabited by myriads of living marine animals, although he may not consider that he is deriving his support from the wreck of a former world. But the laborious researches of the Geologist have explained the causes of these phenomena, which in this province are so abundantly presented to our notice.
"It is evident that the slate and ore containing the shells already mentioned, were once at the bottom of an ancient sea, occupied with numerous species of radiated, molluscous, and crustaceous animals, which then enjoyed a perfect animal existence upon a surface placed in a horizontal position. By some mighty revolution the ground occupied by them has been uplifted, and their native submarine possessions converted into slate, and even iron ore. It has been already observed, that the strata of slate are highly inclined, and in many situations almost vertical. Hence it is impossible that those animals could have been deposited one upon another, or thrown confusedly into an open and perpendicular chasm left void in the earth; this would have been contrary to known laws, and is immediately disproved by the facts observed. If it be true that the primary rocks have been thrown upwards by the expansive force of heat, (a fact which modern Geologists consider fully established,) is it not probable, that the bottom of the sea, with all its corals and shells, then resting upon the melted granite, was also thrown upwards, having its strata broken, distorted, and fixed edgewise, in the manner it is now found. We would not enter upon the arguments by which such opinions are established, they are however such as explain almost all the phenomena of the slate, and its fossil remains.
"But again it may be observed, that the iron ore of Clements is magnetic. It is difficult to suppose that the heat, which rendered the bed of iron ore capable of this singular influence, was derived from that attending the formation of the trap rocks of the North Mountains; an opinion which Messrs. Jackson and Alger consider ' undeniable.' Had it been received from that source, all the rocks between those mountains and the ore would have exhibited the marks of caloric. But such is certainly not the fact; and the trap rocks are placed in a situation indicating a date much later than even the new red sandstone upon which they rest. If it be true that the primary rocks have been formed and elevated by heat, there will be no difficulty in accounting for the magnetic properties of the ore, as that rock is not far distant from the metallic bed."
Every one of the Districts traced by the author seems not only to be extremely rich in respect of those mineral productions which are turned to practical and economical purposes, but of the most striking and interesting geological phenomena: in this latter view,
the Coal Formations appear to have afforded our author the highest treat.
As to the origin of coal, he holds its being chiefly vegetable to be put beyond all doubt by the appearances abundantly manifest in Nova Scotia, where whole trees frequently present themselves, partially converted into the bituminous compound, and still exhibiting the vegetable fibre. While admitting that the operations of causes now active on our globe may be sufficient to account for collections of lignite, which is so common to all countries, what more probable than that many and great changes, and perhaps from natural causes, may have occurred before the flood in lakes and estuaries which from time to time received layers of vegetable matter swept into them! Other materials most likely would mingle with the layers of woody matter, which might produce those alternations that yet remain. But whatever may have been the precise history of the matter, the author of the "Remarks" informs us, that perfectly independent coal fields, or distinct coal measures, exist in the province of which he writes to a great extent, offering a supply of incalculable value; while the vast variety and striking character of the organic remains contained in these fields, are worthy of the research of a Buckland or a Cuvier. He admits, at the same time, that but few of the coal fields in Nova Scotia have been scientifically explored. The result of his own investigations and labours he, however, publishes, which, limited as they must have been compared to the magnitude and importance of the subject, are yet highly deserving of the consideration both of the economist and the man of science. Here are some of the geological features of the district where the coal formation abounds, together with some symptoms of a naturalist's enthusiasm.
"With much labour has the Cobequid Chain of Mountains been traced from one side of the province to the other; and notwithstanding we might claim the original discovery of its continuation and boundaries, and were the first to mark its outline upon the map of the province, no other name than that applied already to one portion of its rugged hills has been bestowed; and until a more appropriate shall be given, we choose to preserve the ancient designation of the natives, and therefore have called it the Cobequid Chain, This chain of mountains seems to preserve an uniform width, which seldom exceeds ten miles. In some places even that distance would much more than reach from side to side of its base. Its course is nearly east and west, until it reaches Mount Thom, where the bifurcation may be observed.
Eastward of the road between Truro and Tatmagouche, the mountains appear to consist chiefly of greywacke and greywacke slate, which are met by the coal measures of Pictou on one side, and those of Cumberland on the other. On the Cobequid Mountains, as they are called, granite, in limited masses, makes its appearance near Mr. Purdy's farm, and is seen at several places along the road. It also forms the top of the 'Sugar Loaf,'