The Botanic Garden, a Poem in Two Parts. Part 1: the Economy of Vegetation

by Erasmus Darwin

GEOLOGICAL RECAPITULATION.

1. The earth was projected along with the other primary planets from the sun, which is supposed to be on fire only on its surface, emitting light without much internal heat like a ball of burning camphor.

2. The rotation of the earth round its axis was occasioned by its greater friction or adhesion to one side of the cavity from which it was ejected; and from this rotation it acquired its spheroidical form. As it cooled in its ascent from the sun its nucleus became harder; and its attendant vapours were condensed, forming the ocean.

3. The masses or mountains of granite, porphery, basalt, and stones of similar structure, were a part of the original nucleus of the earth; or consist of volcanic productions since formed.

4. On this nucleus of granite and basaltes, thus covered by the ocean, were formed the calcareous beds of limestone, marble, chalk, spar, from the exuviae of marine animals; with the flints, or chertz, which accompany them. And were stratified by their having been formed at different and very distant periods of time.

5. The whole terraqueous globe was burst by central fires; islands and continents were raised, consisting of granite or lava in some parts, and of limestone in others; and great vallies were sunk, into which the ocean retired.

6. During these central earthquakes the moon was ejected from the earth, causing new tides; and the earth's axis suffered some change in its inclination, and its rotatory motion was retarded.

7. On some parts of these islands and continents of granite or limestone were gradually produced extensive morasses from the recrements of vegetables and of land animals; and from these morasses, heated by fermentation, were produced clay, marle, sandstone, coal, iron, (with the bases of variety of acids;) all which were stratified by their having been formed at different, and very distant periods of time.

8. In the elevation of the mountains very numerous and deep fissures necessarily were produced. In these fissures many of the metals are formed partly from descending materials, and partly from ascending ones raised in vapour by subterraneous fires. In the fissures of granite or porphery quartz is formed; in the fissures of limestone calcareous spar is produced.

9. During these first great volcanic fires it is probable the atmosphere was either produced, or much increased; a process which is perhaps now going on in the moon; Mr. Herschell having discovered a volcanic crater three miles broad burning on her disk.

10. The summits of the new mountains were cracked into innumerable lozenges by the cold dews or snows falling upon them when red hot. From these summits, which were then twice as high as at present, cubes and lozenges of granite, and basalt, and quartz in some countries, and of marble and flints in others, descended gradually into the valleys, and were rolled together in the beds of rivers, (which were then so large as to occupy the whole valleys, which they now only intersect;) and produced the great beds of gravel, of which many valleys consist.

11. In several parts of the earth's surface subsequent earthquakes, from the fermentation of morasses, have at different periods of time deranged the position of the matters above described. Hence the gravel, which was before in the beds of rivers, has in some places been raised into mountains, along with clay and coal strata which were formed from morasses and washed down from eminences into the beds of rivers or the neighbouring seas, and in part raised again with gravel or marine shells over them; but this has only obtained in few places compared with the general distribution of such materials. Hence there seem to have existed two sources of earthquakes, which have occurred at great distance of time from each other; one from the granite beds in the central parts of the earth, and the other from the morasses on its surface. All the subsequent earthquakes and volcanos of modern days compared with these are of small extent and insignificant effect.

12. Besides the argillaceous sand-stone produced from morasses, which is stratified with clay, and coal, and iron, other great beds of siliceous sand have been formed in the sea by the combination of an unknown acid from morasses, and the calcareous matters of the ocean.

13. The warm waters which are found in many countries, are owing to steam arising from great depths through the fissures of limestone or lava, elevated by subterranean fires, and condensed between the strata of the hills over them; and not from any decomposition of pyrites or manganese near the surface of the earth.

14. The columns of basaltes have been raised by the congelation or expansion of granite beds in the act of cooling from their semi-vitreous fusion.