The Religion of Geology and Its Connected Sciences

by Edward Hitchcock

Now, the oldest rocks in the globe contain crystals, and so do the rocks of all ages, sometimes of the same kind as those produced in the chemist’s laboratory. And they are found to correspond precisely. It matters not whether they were the produce of nature’s laboratory countless ages ago, or of the skill of the nineteenth century,—the same mathematics ruled in their formation with a precision which infinite wisdom alone could secure.

In the second place, the laws of meteorology have ever been the same as at present.

Under meteorological laws I include all atmospheric phenomena. And although we have no direct proof from geology in respect to the more rare of these phenomena, such as the aurora borealis and australis, and transient meteors, yet in respect to the existence of clouds, wind, and rain, the evidence is quite striking. In several places in Europe, and in many in this country, are found, upon layers of the new red sandstone, the distinct impressions of rain drops, made when the rock was fine mud. They correspond precisely with the indentations which falling rain-drops now make upon mud, and they show us that the phenomena of clouds and storms existed in that remote period, and that the vapor was condensed as at present. In the fact that the animals entombed in the rocks of various ages are found to have had organs of respiration, we also infer the existence of an atmosphere analogous to that which we now breathe. The rain-drops enable us to proceed one step farther; for often they are elongated in one direction, showing that they struck the ground obliquely, doubtless in consequence of wind. In short, the facts stated enable us to infer, with strong probability, that atmospheric phenomena were then essentially the same as at present; and analogy leads us to a similar conclusion as to all the past periods of the world’s history, certainly since animals were placed upon it. What a curious register do these rain-drops present us! an engraving on stone of a shower that fell thousands and thousands of ages ago! They often become, too, an anemoscope, pointing out the direction of the wind, while the petrified surface shows us just how many drops fell, quite as accurately as the most delicate pluviameter. What events in the earth’s pre-Adamic history would seem less likely to come down to us than the pattering of a shower?

In the third place, the agents of geological change appear to have been always the same on the earth.

Whoever goes into a careful examination of the rocks will soon become satisfied that no fragment of them all remains in the condition in which it was originally created. Whatever was the original form in which matter was produced, there is no longer any example of it to be found. The evidence of these changes is as strong almost as that constant changes are going on in human society. And we find them constantly progressing among the rocks, as well as among men; nor do the agents by which they are produced appear to have been ever different from those now in operation. The two most important are heat and water; and it is doubtful whether there is a single particle of the globe which has not experienced the metamorphic action of the one or the other. Indeed, it is nearly certain that every portion of the globe has been melted, if not volatilized. All the unstratified rocks have certainly been fused, and probably all the stratified rocks originated from the unstratified, and have been modified by water and heat. In many of these rocks, especially the oldest, we perceive evidence of the joint action of both these agents. Evidently they were once aqueous deposits; but they appear to have been subsequently subjected to powerful heat. As we ascend on the scale of the stratified rocks, the marks of fire diminish, and those of water multiply, so that the latest are mere mechanical or chemical depositions from water.

In these facts, then, we see proof that heat and water have been the chief agents of geological change since the first formation of a solid crust on the globe; for some of the rocks now accessible, as already stated, date their origin at that early period. We might also trace back the agency of heat much farther, if the hypothesis adopted by not a few eminent geologists be true, which supposes the earth to have been once in a gaseous state from intense heat. But to press this point will add very little to my argument, even could I sustain it by plausible reasoning. I will only say, that, so far as we know any thing of the state of the earth previous to the consolidation of its crust, heat appears to have been the chief agent concerned in its geological changes.

Among other agencies of less importance, that have always operated geologically, is gravity. Its chief effect, at present is to bring the earth’s surface nearer and nearer to a level, by causing the materials, which other agencies have loosened from its salient parts, to subside into its cavities and valleys. It also condenses many substances from a gaseous to a liquid or solid state, especially those deep in the earth’s crust, and thus brings the particles more within the reach of cohesive attraction and chemical affinity, often changing the constitution, and always the solidity, of bodies. And in the position of the ancient mechanical rocks, occupying as they do the former basins of the surface, and in the superior consolidation of the earlier strata, we find proof of the action of gravity in all past geological time.

Electricity too, in the form of galvanism, has never been idle. We have reason to think that it operates at this moment in accumulating metallic ores in veins; and this segregation appears to have operated in all ages, not only in filling veins, but also, probably, in giving a laminated character and jointed structure to mountains of slate, as well as a concretionary and prismatic form to others.

Last, though not least, we may reckon among the agents of geological change the forces of cohesion and affinity. When water and heat, gravity and galvanism, have brought the atoms of bodies into a proper state, these agents are always ready to change their form and constitution; and they have ever been at hand to operate by the same laws, and we witness their effects in the oldest as well as the newest rocks found in the earth’s crust. This point, however, has been sufficiently considered, when treating of the unvarying uniformity of the laws of chemistry and crystallography.

But though the nature of the agencies above considered has never changed, the intensity or amount of their action has varied; how much is a point not yet settled among geologists. Some regard that intensity, as it has existed during the present or alluvial period, as a standard for all preceding periods; that is, the intensity of these forces has never varied more during any period of the earth’s history than it has since the alluvial period commenced. Most geologists, however, regard this as an extreme opinion, and think they see evidence in geology of a far greater intensity in these agencies in past periods than exists at present. They think they have proof that the world was once only a molten mass of matter, and some evidence that previously it was in a state of vapor. They believe that vast mountains, and even continents, have sometimes been thrown up from the ocean’s bed by a single mighty paroxysmal effort; and such effects they know to be far greater than the causes of change now in operation can produce, without a vast increase of their intensity. But this question need neither be discussed nor decided for the sake of my present argument, since my object is to prove an identity in the nature and laws, not in the intensity, of geological agencies.