46 A MANUAL Or THE CONIFERS. 



have lasted at least a million of years,* is inferred from the identity 

 of its f ossiferous remains found in different parts of the world." 



In the period immediately succeeding the Coal Measures, the luxuriance 

 of vegetation appears to have diminished. As if the earth were already 

 exhausted, one form after another of the Carboniferous vegetation 

 disappears. The prevalent forms in the Permian System are still 

 Sigillarias, Calamites, and Coniferse of the Araucaria division; Cycads 

 attain their maximum developement and Palms first appear. 



A different vegetation characterises the Secondary or Mesozoic strata. 

 The Coniferse began in the Devonian, attained a maximum in the 

 Coal Measures, again diminish in the Permian. In the Triassic 

 System, the oldest in the series, Coniferse and Ferns formed the main 

 part of the forest, the principal species of the former being Voltzia 

 and Albertia, the first a lofty tree not unlike our Cryptomeria, and 

 the latter had broad leaves penetrated by longitudinal veins, t In 

 the next in succession, the Jurassic system, consisting of beds of 

 argillaceous limestone, marls, and clays called Lias and Oolite, the 

 prevalent forms of the forests consisted of Cycads, associated with 

 numerous Coniferae, nearly related to our Araucarias and Thuias, of 

 which remains have been found in the Lias at Whitby ; - in the 

 inferior Oolite at Bruton in Somersetshire ; and in the Purbeck beds 

 in Dorsetshire. The underwood of the forests still consisted of Fems 

 along with fleshy Fungi ; the Calamites had disappeared and were 

 replaced by other Equisetaeese (Horse tails), scarcely exceeding our own 

 in size. In the Cretaceous System, the first Dicotyledonous trees appear, 

 these were allied to the Walnuts, Oaks, and Figs of our Flora; 

 Cycads diminish in number, but Coniferae are still . abundant, the most 

 common- in the upper Cretaceous period belonging to a genus called 

 Cycadopteris and hardly separable from Sequoia (Wellingtonia), and 

 of which both cones and branches are preserved. Species of Araucaria 

 like those of Australia are also found associated with many Proteacese 

 (Grevilleas, Hakeas; &c), now so abundant in the same quarter of 

 the globe. J 



The lowest of the Tertiary or Cainozoic Eocks are the Eocene. 

 In this period Dicotyledonous trees began to contest the supremacy 

 with Cycads and Cryptogamia. Trees allied to the gigantic Sequoias 

 of California, the Cunninghamia and Glyptostrobus of China, which 

 first appear in the preceding system, attain their greatest development 

 in this and the succeeding period, the Miocene, in which remains 

 have been found in Greenland, Iceland, Britain, Switzerland, and 

 Italy. Pines belonging to the three-leaved section, are proved to 

 have existed in Europe in this period. In the middle Tertiary are 



* Sir C. Lyell, Geology, p. 489. 

 t Thome's Structural and Physiological Botany, p. 427, 

 % Sir C, Lyell, Geology, pp. 426, 407, 371, 



