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Updated: May 9, 2025
It is believed in Venezuela as in Egypt that petrified wood is formed in our times. I found this dicotyledonous petrified wood only at the surface of the soil and not inclosed in the sandstone of the Llanos. M. Caillaud made the same observation on going to the Oasis of Siwa. It is not easy, when several formations are not perfectly developed, to determine the age of arenaceous rocks.
I do not suppose that the dead soul of Peter Bell, of whom the great poet of nature says, A primrose by the river's brim, A yellow primrose was to him, And it was nothing more, would have been a whit roused from its apathy by the information that the primrose is a Dicotyledonous Exogen, with a monopetalous corolla and central placentation.
The same phenomena are repeated in the most distant regions; and, instead of designating those vast treeless plains in accordance with the nature of the plants they produce, it seems natural to class them into deserts, steppes, or savannahs; into bare lands without any appearance of vegetation, and lands covered with gramina or small plants of the dicotyledonous tribe.
There is also much silicified wood, both common dicotyledonous and coniferous: a section of one specimen in the direction of the medullary rays has, as I am informed by Mr. R. Brown, the discs in a double row placed alternately, and not opposite as in the true Araucaria.
Lycett, "must have been deposited in a shallow sea, where strong currents prevailed, for there are frequent changes in the mineral character of the deposit, and some beds exhibit false stratification. In others, heaps of broken shells are mingled with pebbles of rocks foreign to the neighbourhood, and with fragments of abraded madrepores, dicotyledonous wood, and crabs' claws.
These plants occur in fourteen of the beds namely, in two of the clays, and the rest in the lignites. One of the beds is a perfect mat of the debris of a coniferous tree, called by Heer Sequoia Couttsiae, intermixed with leaves of ferns. Another bed is full of the large rhizomes of ferns, while two others are rich in dicotyledonous leaves.
I find on examination, that when irregularly shaped stones are embedded in the roots of trees, small parcels of earth are very frequently enclosed in their interstices and behind them, so perfectly that not a particle could be washed away in the longest transport: out of one small portion of earth thus completely enclosed by wood in an oak about 50 years old, three dicotyledonous plants germinated: I am certain of the accuracy of this observation.
In the first stratified rocks in which any organic remains are found, the highest animals are fishes, and the highest plants are cryptogams; in the middle periods reptiles come in, accompanied by fern and moss forests; in later times quadrupeds are introduced, with a dicotyledonous vegetation.
The only phaenogamous plants were constitute any feature in the coal are the coniferae; monocotyledonous angiosperms appear to have been very rare, and the dicotyledonous, with one or two doubtful exceptions, were wanting.
At the close of the middle geological ages and the opening of the Tertiary periods, the Monocotyledons become abundant, the first plants with flower and inclosed seed, though with no true floral envelope: but not until the two last epochs of the Tertiary age do we find in any number the Dicotyledonous plants, in which flower and fruit rise to their highest perfection.
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