Identifier: geology00cham (find matches)
Title: Geology
Year: 1907 (1900s)
Authors: Chamberlin, Thomas C. (Thomas Chrowder), 1843-1928 Salisbury, Rollin D., 1859- joint author
Subjects: Geology
Publisher: New York, H. Holt and co.
Contributing Library: Internet Archive
Digitizing Sponsor: Internet Archive

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us and the pine above mentioned. Some of these remainedin the northern regions into the early Cenozoic. Previous to this period, and in its earlier stages, monocotyledonsplayed but an insignificant part in the floral record, but they nowbegan to assume importance. Many palms were present before theclose of the period, some of wThich at least were closely allied to existingforms. Their presence in northern latitudes implies a mild climate.Of even more interest, because of their relations to the evolution ofgrazing animals, was the appearance of grasses, which do not, how-ever, appear to have attained prominence thus early. It is worthy ofremark here that the Cretaceous revolution in vegetation was notonly great as a phytological event, but was at least susceptible ofprofound influence on zoological evolution, for it brought in new andricher supplies of food in the form of seeds, fruits, and fodder. Atpresent, neither the ferns, equiseta, cycads, nor conifers furnish food J 74 Gl OLOQY.
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Fig. 408.—A Group of Fossil Leaves of Typical Cretaceous Plants from theDakota Horizon: a, Liriodendron giganteum Lesq.; b, Myrica longa Heer; c,Magnolia pseudo-acuminata Lesq.; d, Sterculia mucronata Lesq.; e, Quercus sus-pecta Lesq.; /, Viburnum, incequilctterale Lesq.; g, Betulites westi, var. subinte-grifolius Lesq.; h, Sassafras subintegrijolium Lesq.; i, Ficus inwqnalis Lesq. THE CRETACEOUS PERIOD. 175 for any large part of the animal life. The seeds of the conifers areindeed much eaten by certain birds and rodents, but their foliageis little sought by the leading herbivores. The introduction, there-fore, of the dicotyledons, the great bearers of fruits and nuts, and ofthe monocotyledons, the greatest of grain and fodder producers, wasthe groundwork for a profound evolution of herbiverous and frugiverousland animals, and these in turn, for the development of the animalsthat prey upon them. A zoological revolution, as extraordinary asthe phytological one, might naturally be ant

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