Geological classification.

Theories of the earth.

very different material or of different materials, to prepare a place for the residence of animals and the growth of vegetables. The outer shell or crust of the earth does not always exist in the same form. All that is now loose soil, in Geology called diluvium and alluvium, has existed in the form of rocks, and much that is now in a consolidated form, has existed in the form of diluvium and alluvium. From certain causes, with a considerable portion of the outward crust, there have been alternations in this respect. From the effects of the atmosphere, the attrition of rain, running streams, the beating and rolling of the ocean, frost, and a variety of other causes, solid matter has been broken down and pulverized; and from protracted rest, heat, pressure, a cementing principle, and other causes, loose soil has been consolidated and converted into thick beds of rocks.

All the different rocks upon the surface of the globe are divided into four classes. The names of the four classes are, primary or primitive, transition or intermediate, secondary, and tertiary. Besides these, some geologists have a fifth class, called quaternary, but generally what are called quarternary are included under the head of tertiary. These were formed, one after the other, in the order they have been named.

There have been a great number of theories formed, in regard to the earth, some of them so inconsistent as to be exploded as soon as they were promulgated. Those theories which have borne the test of the greatest scrutiny, are what has been called the Neptunian, which accounts for all the rocks from a watery origin, and the Vulcanian, which ascribes them to an igneous or fiery origin. Some persons are averse to theories; and when they are not founded on facts and rational principles, they do only serve to mislead. It is difficult, however, to com

Vulcanian, or igneous theory.

Mosaic account.

municate information to any great extent without some regular theory.

The Vulcanian theory, which ascribes the formation of the rocks to an igneous origin, seems to have the most facts to support it; and that is the theory most believed in by those who have had the best opportunity to judge.

According to this theory, or that modification of it which seems to be the most rational, the earth was once an entire body of igneous materials. It existed in this state for a long time; and when the heat at its surface was sufficiently dissipated, it began to be incrusted over, just as water freezes, when the temperature of the weather is below 32 F. This incrustation extended deeper and deeper, until the whole of that class of rocks was formed denominated primitive. This, to judge from appearances, took place when the earth was comparatively in an undisturbed state; and the consolidation extended round the entire globe. The other rocks were formed afterwards, from different causes, and in a different manner.

From a variety of circumstances, and a multiplicity of evidences, we have the greatest reason to suppose that the earth, since it was first spoken into existence, has undergone many great changes. The account of the creation given by Moses shows this. Its primordial state, according to this sacred historian, was "without form and void." This was its embryo state, and was probably a very different state from what some people imagine. The second state, as mentioned by the same historian, was when a firmament was formed. The third state was when the waters under the whole heavens were gathered unto one place, and the dry land was made to appear, so that the earth brought forth grass, herb yielding seed after his kind, and fruit-tree yielding fruit after his kind. The fourth was when lights were placed in the heavens,

History of the creation.

Stages of the earth's existence.

when day was divided from night, and when days, and seasons, and years, were meted out by the heavenly bodies. The fifth was when the waters brought forth abundantly the moving creatures that have life-whales and everything that moveth in the waters, and every winged fowl after his kind. Creatures which could scarcely be said to have life, and that could not be called moving creatures, such as corallites and other un-locomotive animals, were doubtless created when the earth was in a different state. The sixth state was when the larger and more perfect land animals were created-cattle, other beasts of the earth, and man. This shows that the earth has existed in different states. The only difficulty is to explain how all these changes could take place in so short a space as six days. The most rational method is, to suppose that time was not measured then as it is now. The sun and moon were not created until the fourth day; of course it is irrational to suppose that it was measured by days, and months, and years. Furthermore, one day with the Lord is as a thousand years, and a thousand years as one day. A rational account of all these states and changes could be exhibited, coinciding with the geological construction of the globe, but it would prolong this essay to too great an extent.

There are other changes which it is necessary to speak of. The first, or primordial state of the earth, might with propriety be subdivided into three states. First, when the epithet "without form and void" would with most propriety apply to it; second, when it was in the form of a fiery abyss; and third, when it was in the form of a watery abyss. The last was that form of it, previous to the time when the waters over the whole earth were separated unto one place, and the form which has so often been spoken of under the name of the "watery abyss," by philosophers of every age.

Existence of a fiery abyss.

Successive formations of rocks.

The existence of a fiery abyss is proved from a great variety of circumstances, and acceded to by the most enlightened geologists. Formerly, such a belief was thought to be unconformable to the sacred oracles, but latterly it is supposed to coincide with them. The most prominent evidences of the earth's having formerly existed in the form of a fiery abyss, are the facts that the primary rocks have the appearance of an igneous origin, the evidences of a tropical temperature having formerly existed in high northern and southern latitudes, and the increase of temperature in the descent into the internal parts of the earth. There are innumerable evidences to show that the earth is in a state of igneous fusion at its centre at the present period. This, with the testimony which has been adduced, is sufficient to establish the fact that it was formerly an entire body of fire.

The primary rocks having been composed first, formed the basis of all the other classes. They were formed as before stated, by the cooling and consolidation of the mass at its surface, just as water freezes. As they are not all alike, the circumstances under which they were formed were sufficiently unlike to account for this want of conformity. The other classes were formed afterwards, succeeding each other in the order they have been mentioned. They are supposed to have been formed of the three-fold combination of the ruins of former rocks, volcanic and sub-marine eruptions from the ignited mass, and fossil remains. Being composed at different periods, and the materials of which they were formed being somewhat different from each other, there is sufficient variation in their construction to render it proper to divide them into classes.

What is meant by former ruins, is the broken and pulverized condition that large portions of rocks have from the earliest periods existed in. From what might

Changes in the condition of the earth, and of the rocks.

be called an elemental strife, rocks in many places were broken in pieces, lifted from their former positions, jammed and dashed against each other, and pulverized to atoms. These, when the other materials which have been mentioned had become mingled with them, and they had reposed long enough to become consolidated, were reconverted into rocks, and one after the other of the classes were formed according to the period when they were brought into existence. Should all the loose soil now reposing upon the more solid materials of the earth, mingled as it is with fragments of former rocks, volcanic eruptions and fossil remains, be thus consolidated, it would form a class similar to those which were formed in succession to each other after the primary class.

Notwithstanding the different classes were composed. one after the other, reposing upon each other as they were formed, yet when our observation is extended to those which are in view, we find them in many places jumbled promiscuously together-all the different classes mingled upon the same spot. Lest this should not be fully comprehended, a little further explanation will be devoted to this particular.

It has been seen that the earth has not always existed in that uniform, quiet, and unchanging condition we are inclined to suppose. Changes are continually taking place in our own times, and history informs us of greater changes than any which are known to predominate at the present period. Judging from this, and from what seem to be certain criterions of change, they existed in a greater degree previous to the period when history began to record the facts, than since that date. Wherever we cast our eyes, we behold something to convince us of this. A large portion of the smaller rocks seem to be only fragments of larger ones. Rocks, wherever they are found,