Fig. 116.—Cellaria loriculata.
(Recent Polyzoa.)
This last and most remarkable species of Zoophyte presents itself in great masses many yards in circumference, and necessitates a long period of time for its production. This assemblage of little creatures living under the waters but only at a small depth beneath the surface, as Mr. Darwin has demonstrated, has nevertheless produced banks, or rather islets, of considerable extent, which at one time constituted veritable reefs rising out of the ocean. These reefs were principally constructed in the Jurassic period, and their extreme abundance is one of the characteristics of this geological age. The same phenomenon continues in our day, but by the agency of a new race of zoophytes, which carry on their operations, preparing a new continent, probably, in the atolls of the Pacific Ocean. (See [Fig. 108], p. 240.)
Fig. 117.
1, Otopteris dubia; 2, Otopteris obtusa; 3, Otopteris acuminata; 4, Otopteris cuneata.
The flora of the epoch was very rich. The Ferns continue to exist, but their size and bearing were sensibly inferior to what they had been in the preceding period. Among them Otopteris, distinguished for its simply pinnated leaves, whose leaflets are auriculate at the base: of the five species, 1, O. dubia; and 2, O. obtusa; and 3, O. acuminata; and 4, O. cuneata ([Fig. 117]), are from the Oolite. In addition to these we may name Coniopteris Murrayana, Pecopteris Desnoyersii, Pachypteris lanceolata, and Phlebopteris Phillipsii; and among the Lycopods, Lycopodus falcatus.
The vegetation of this epoch has a peculiar facies, from the presence of the family of the Pandanaceæ, or screw-pines, so remarkable for their aërial roots, and for the magnificent tuft of leaves which terminates their branches. Neither the leaves nor the roots of these plants have, however, been found in the fossil state, but we possess specimens of their large and spherical fruit, which leave no room for doubt as to the nature of the entire plant.
The Cycads were still represented by the Zamias, and by many species of Pterophyllum. The Conifers, that grand family of recent times, to which the pines, firs, and other trees of our northern forests belong, began to occupy an important part in the world’s vegetation from this epoch. The earliest Conifers belonged to the genera Thuites, Taxites, and Brachyphyllum. The Thuites were true Thuyas, evergreen trees of the present epoch, with compressed branches, small imbricated and serrated leaves, somewhat resembling those of the Cypress, but distinguished by many points of special organisation. The Taxites have been referred, with some doubts, to the Yews. Finally, the Brachyphyllum were trees which, according to the characteristics of their vegetation, seem to have approached nearly to two existing genera, the Arthotaxis of Tasmania, and the Weddringtonias of South Africa. The leaves of the Brachyphyllum are short and fleshy, with a large and rhomboidal base.