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tice of the world or its spirit that stands most opposed to religion? Avails it any thing to renounce the one and keep the other? I saw no CONSISTENCY between the morning's discourse and the evening's, except in volubility of speech.
CONVERSATIONS ON GEOLOGY.
INTRODUCTORY-STRATA-NODULES-VEINS, MRS. L. We have determined, I think, on Geology as the future subject of our evening conversations.
MATILDA.-I hope so; for my curiosity is excited by what you said last night. For the first time I looked out upon the hills this morning, with a desire to know what was beneath their verdant covering; and where the broken cliff laid bare the soil, began to consider of its form and colouring, as if I had already taken up the profession of Geologist, and peeped into the secrets of our mother earth. You mentioned that the science of Geology is of very recent date--where had it a beginning?
Mrs. L. A recent writer has remarked, that “ Geology, as a branch of inductive science, is of very modern date; for though the attention of men has long been turned to the theory of the earth, the formation of such a theory is incompatible with any but an advanced state of physical knowledge. There appear, indeed, few studies of more difficulty; none in which the subject is more complex-appearances so diversified and scattered and where the causes that have operated are so remote from the sphere of ordinary observation." “ About a hundred years ago, the attention of the learned began to be directed to these great phænomena, and Burnet, Woodward, and others, devised theories to explain them. Their attempts, as might be expected from the small number of facts then known, were very defective.” The systems of these crude Geologists are scarcely worth noticing, except it were to prove how slowly knowledge grows, and what strange fancies men can persuade themselves and others to accept as truth. Burnet supposed that at the creation the elements separated themselves from a fluid mass; the heaviest sinking to the bottom, formed the solid earth, while the lighter water, and still lighter air, each took its respective station. In this state he supposed the earth to have been a smooth and equal surface, and its position being also different, clothed with the charms of a perpetual spring; 'till in the lapse of years, by the heat of the sun, the surface cracked and divided; and, finally, at the disruption of the flood, attained its present broken and uneven surface, the water subsiding into beds opened to them by this breaking of the earth beneath. Leibnitz 'wrote to prove the earth to have been in a state of combustion for many ages, and at length to have gone out for want of fuel; a glassy crust of sand and gravel was thus formed; and as the globe cooled, the water, which had before been kept in the state of steam, assumed a fluidity, and falling to the earth, produced the ocean. The learned Buffon, whose object always was to get rid at once of creation and its Creator, produced a system suited to his purpose. Having first persuaded us that our planet had been struck off from the sun by the blow of a comet, and so put itself in motion for ever, he proceeds to prove that every thing upon it also arranged itself by degrees into its present form—the rivers cutting out their own beds, and so on, through all those wonderful works of nature, of the glory of which he was determined to deprive their great Originator.
“ From these speculations, Geology was rescued by the appearance of Werner. This great man first applied to it that spirit of observation and calm deduction which had already so greatly advanced other branches of physics: he first elevated it to the dignity of a science ; and though his cosmogonical hypothesis is now almost universally abandoned, yet to him we are indebted for awakening a spirit of enquiry which has extended itself to every branch of the civilized world, while he has also pointed out those facts which are most worthy of observation, and from which any knowledge of the previous states of the globe have been derived." So much I have said, or rather quoted, in answer to your question respecting the origin of Geological science; but I by no means intend to lead you into disputed systems and vague conjectures of the past-but rather to inform you of the present state of the globe as far as it is known, leaving it to the learned to decide how it came so: occasionally I shall mention their more reasonable conclusions still aware, that whatever I may tell you on that subject, or whepcesoever I may draw my authority, , some Geologist of another school will say we are misinformed.
ANNE.-Do you not think this uncertainty takes something from the pleasure of the pursuit?
MRs. L.--I confess I do not-on the contrary, when we have gathered what is already known and proved, we have the animating expectation of hearing something new. Every year may be expected to produce some new discovery, or the confirmation of some previous conjecture: and though we admit the uncertainty and doubtfulness of every thing that respects the past, the actual state of the globe is tolerably well ascertained. So much as is known on the interesting subject, we may do well to add to our store of information--more will doubtless be hereafter discovered: but when all is known, and all discovered that is within the reach of mortal ken, there is no doubt but we must end, here as every where, in the simplicity of childlike ignorance-be content to take the word of God for what we cannot discover, and believe that things are so because he made them so, and that he made them so because it pleased him. I believe, be our studies what they may, they all must end in this.
ANNE.-And now I think we may proceed with our enquiries.
Mrs. L.-I'shall begin with explaining the meaning of some of those terms which I imagine you do not understand, and which are of most frequent occurrence. You will observe that, “the substances which form the surface of the earth, occur in STRATA, NODULES' or VEINS. The Strata are beds, which preserve through a considerable extent, a certain degree of parallellism ip their Superior and Inferior Planes.” You understand these terms, I trust.
ANNE.-I understand parallellism to be the running of two lines in the same direction, (Plate I. Fig. 1,) and I suppose the Superior Plane (a) to be the upper, the Inferior Plane (b), the under surface of a Stratum
Mrs. L.-Exactly so-endeavour to remember that this is meant whenever these terms are used. “ Another character of Strata is that their length and breadth greatly exceed their thickness. The thickness varies from many feet to much less than an inch. Different Strata of the same or of different substances repose upon each other, and the undermost is then considered to be of earlier formation"—that is, by some means deposited there previously to the one above it—which you must remember as the usual meaning of the term FORMATION. · Now it is obvious that if all the Strata were perfectly horizontal, as suppose in Fig. 2., we should only be acquainted with the highest in the series, unless we sunk shafts through them; but Providence, in this, as in other respects, making provision for the comfort and happiness of mankind, has disposed these Strata at angles more or less inclined towards the horizon: the consequence of which arrangement is, that many Strata successively appear at the surface, and afford us the several advantages arising from the difference of soil and mineral products,". Do you understand this entirely?
MATILDA. I think so. If the Strata that compose
the earth's surface were placed upon one another horizontally, as in Fig. 2, we should always have the same at the top, consequently should have difficulty in obtaining the products of those beneath-whereas, if inclining or aslant, as in Fig. 3., each may successively appear on the surface, and yet not actually change places with the one above it.
MRS. L.-That is the case. And this arrangement has given rise to certain technical expressions which it is necessary you should fully understand, as they will be continually recurring. Where the edges of the inclined Strata are uncovered and visible upon the surface, (a a a, Fig. 3.) they are said to rise to the day, to basset, or crop-out—the points at which the edges of such Strata appear, being consequently called the Outcrop, or Basset. That part of the horizon to which the Out-crop is directed, is called the Direction of that Stratum-as to the East, the North-west, &c. The degree in which the Plane or surface of the Stratum differs from a horizontal position, is called its INCLINA: TION, or Dip, and is measured by the degrees of a circle-thus, Fig. 4.--the Stratum is said to have an Inclination of forty-five degrees, because the depression of its Plane (a) is forty-five degrees from the horizontal line (b). I conclude you know that the quarter of a circle is ninety degrees. I have traced the half circle that you may better understand me. In the term Dip is also included its tendency towards some point of the horizon, when not vertical.
“ NODULES are masses of irregular form, which are found imbedded in, and surrounded by the regular Strata: they vary greatly in size, from a foot to many miles in length.”—(6. Fig. 4.)
• Veins are distinguished from regular Strata, by their great irregularity, their laminar and thread-like forms, and by their intersecting the Strata and Nodules of other rocks—they also intersect each other. Veins vary in thickness from many yards to that of a hair. In