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What I was reading last night

From The American Quarterly Review, No. 17 (volume 9). March, 1831.

[with a nod towards Green Gabbro]

…different latitude, for every successive day in the year, and during each varying hour of the day.

It has been attempted to explain this change that has unquestionably taken place in the temperature of climate, by conceiving a change in the situation of the earth’s axis. This hypothesis, however, is shown to be untenable by the calculations of physical astronomy: no other cause then remains but an actual change in the condition of the earth itself.

The most remarkable of all the phenomena which the earth presents, are the great changes of weight that have taken place in identical formations which must have arisen from the prevalence of water, and therefore nearly if not exactly upon the same level. The primitive or lowest stratified rocks, probably had not water for their cause; still, however, they must have been in the fluid state, and these are not only found beneath all other rocks, and in the lowest places to which the industry of man has penetrated, but they also rise and form the greatest part in bulk of many of the highest mountains; indeed, if we except volcanic mountains, of all the more elevated masses. The transition and secondary formations are subject to similar although less changes of level, rising, as has been seen, to the tops of the Pyrenees, and to even a greater height on the sides of the Andes. The tertiary or superior formations are found in Italy and Sicily, forming mountains several thousand feet in height, while the latest of all, the diluvial with its embedded mammalia, exists in the lofty table land of Quito. The inference is irresistible, that we do not now find these deposits at the levels where they were left by the ocean, as in the case of the primitive rocks by their own crystallization from a fluid state, but that they have been altered in their positions by actions of a character totally distinct from that by which they were originally formed.

This inference is still further confirmed by the great and sudden changes of level that are frequently to be seen in similar strata, faults, as they are styled by miners, in which the same bed has its level sometimes changed hundreds, nay even thousands of feet. These faults, if in greatest abundance in the more ancient rocks, are to be found even in the newest, and sometimes affect several formations incumbent on each other, of ages the most different. Thus, then, we have distinct and conclusive evidence, that as we inferred from theory, the solid crust of the globe has been shattered and fractured repeatedly, and at all the different epochs of its history. This fracturing and cracking we have shown, must, in conformity with strict mechanical laws, have been attended with the rise of the molten liquid from beneath, which ought in some cases to have formed veins and dykes, in the places where the fractures occurred. It is however possible, that the rise of the fluid from beneath, may not have taken place where the pressure occurred; but it would then have been compelled by hydrostatic pressure, to issue at some other point, breaking and tearing the weaker parts of the solid crust, in order to afford itself a vent.

The latter class of phenomena are still in action, and we have evident traces of their occurrence in all the different stages of the world’s existence; of the former it will also be seen there is conclusive evidence.

The visible effects of a subterranean heat, are most frequently met with at the present day in the form of volcanoes. Of these, there are not only a great number in activity, but there are still more that have been certainly active since the last great change that the surface of the earth has undergone.

That part of the great group of mountains which we have before described, which lies in the new continent, contains many active volcanoes, and others but recently extinct. Terra del Fuego, as its very name imports, is the seat of many; Chili has several; in Peru are to be noted Arequipa, Pichinca, and Cotapaxi; while Chimborazo is obviously one that has become extinct at a period not remote. Passing the Isthmus of Panama, we find the volcanoes of Guatimala and Nicaragua almost infinite in number. In Mexico, are Orezaba, Popocatepetl, and Jorullo; the last of which first rose from beneath the surface in 1759. California has five active volcanoes; and we know, from the observations of La Perouse and Cook, that they also exist along the north-western coast of America. Mount St. Elias, in particular, was seen in a state of eruption. These mountains connect those of Mexico with the volcanoes of the Aleutian islands and of the peninsula of Alaska, which continue the system towards Kamtschatka, in which peninsula there are three of great violence. We have seen some proofs, that there are active volcanoes to the north-west of China, but none now exist in Thibet; and the action that once took place there has sought new vents, in regions more near to the present bed of the ocean. Thus, Japan has eight volcanoes, Formosa several, and, in proceeding to the south, the land of volcanic action widens, and becomes of immense extent. It embraces the Philippine, Marian, and Molucca islands, Java, Sumatra, Queen Charlotte’s islands, and the New-Hebrides. The active volcanoes of Europe and western Asia are few in number; but those that are extinct form a great system, in which the active ones are included, and which seems to spread in the form of a belt, from the Caspian sea to the Atlantic. Volcanic action still occurs on the shores of the Caspian. In the chain of Elburg is a lofty mountain that still emits smoke, and around whose base are several distinct craters. Syria and Palestine abound in volcanic appearances, of which the great crater that has swallowed…

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