. The geological history of plants [microform]. Paleobotany; Paléobotanique. 138 THE GEOLOGICAL HISTORY OF PLANTS. 1; :: ill? M Ml H II' to that of the coal period is that of warm, temperate re- gions in the southern hemisphere. It is not properly a tropical flora, nor is it the flora of a cold region, but rather indicative of a moist and equable climate. Still,. Fio. 63.— Walchia imbricatula, S. N., Permian, Prince Edward Island. we must bear in mind that we may often be mistaken in reasoning as to the temperature required by extinct species of plants, differing from .hose now in existence. F
. The geological history of plants [microform]. Paleobotany; Paléobotanique. 138 THE GEOLOGICAL HISTORY OF PLANTS. 1; :: ill? M Ml H II' to that of the coal period is that of warm, temperate re- gions in the southern hemisphere. It is not properly a tropical flora, nor is it the flora of a cold region, but rather indicative of a moist and equable climate. Still,. Fio. 63.— Walchia imbricatula, S. N., Permian, Prince Edward Island. we must bear in mind that we may often be mistaken in reasoning as to the temperature required by extinct species of plants, differing from .hose now in existence. Further, we must not assume that the climatal conditions of the northern hemisphere were in the coal period at all similar to those which now prevail. As Sir Charles Lyell has shown, a less amount of land in the higher latitudes would greatly modify climates, and there is every reason to believe that in the coal period there was less land than now. Further, it has been shown by Tyndall that a very small additional amount of carbonic acid in the atmos- phere would, by obstructing the radiation of heat from the earth, produce almost the effect of a glass roof or con- servatory, extending over the whole world. Again, there is much in the structure of the leaves of the coal-plants, as well as in the vast amount of carbon which they ac- cumulated in the form of coal, and the characteristics of the animal life of the period, to indicate, on independent. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Dawson, J. W. (John William), Sir, 1820-1899. New York : D. Appleton
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectpaleobo, bookyear1888
