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Updated: May 23, 2025
The lower is called the MISSISSIPPIAN, from the outcrop of its formations along the Mississippi River in central and southern Illinois and the adjacent portions of Iowa and Missouri. The upper series is named the PERMIAN, from the province of Perm in Russia.
Now we saw that, during the Permian, Gondwana Land was heavily coated with ice, and it seems natural to suppose that the severe cold which the glacial fields would give to the whole southern continent was the great agency in the evolution of the highest type of the animal world. From this southern land the new-born mammals spread northward and eastward with great rapidity.
Pliocene, miocene, eocene, cretaceous, jurassic, triassic, permian, carboniferous, devonian, silurian, or primitive was all one to me. But the Professor, no doubt, was pursuing his observations or taking notes, for in one of our halts he said to me: "The farther I go the more confidence I feel. The order of these volcanic formations affords the strongest confirmation to the theories of Davy.
These zones did not exist before the Pliocene period, and it is not at all clear that any redistribution of currents in earlier times could have had such remarkable consequences. The same difficulty applies to wind-currents. On the other hand, we have already, in discussing the Permian glaciation, discovered two agencies which are very effective in lowering the temperature of the earth.
Now, in imagination, restore these cliffs of Permian, Triassic, Jurassic and even Cretaceous strata over the whole Canyon platform. Red Butte, which is the prominent landmark seen from the railway on the right, when going from Williams to the Canyon, is said to be a remnant of the Permian. Deposition of Strata in Shallow Water.
The change from a coat of scales to a coat of feathers obviously means adaptation to a low temperature, and there is nothing to prevent us from locating it in the Triassic, and indeed no later known period of cold in which to place it. It is much clearer that the mammals were a product of the Permian revolution.
The meridian altitude of the fourth day must have been reached where for the first time the covering of vapor and clouds of the earthly atmosphere permanently parted, and sun, moon, and stars became visible: and geology finds this time in the period which lies between the carboniferous period and the trias in the Permian period, as it is called in England, in the dyas of the fossiliferous and of cupriferous slate and Zechstein, as we call it in Germany.
The reptiles, again, are a class in which the biggest modern forms are simply nowhere beside the gigantic extinct species. First appearing on the earth at the very close of the vast primary periods in the Permian age they attained in secondary times the most colossal proportions, and have certainly never since been exceeded in size by any later forms of life in whatever direction.
In effect it corresponds very closely to the Permian Revolution.
We can but estimate how many species of animals and plants were exterminated, and the reader must dimly imagine the myriads of living things that are comprised in each species. An earlier American geologist, Professor Le Conte, said that not a single Carboniferous species crossed the line of the Permian revolution.
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