The Oolitic seas of this series contained Fishes belonging to the genera Asteracanthus, Strephodes, Lepidotus, and Microdon. The Cephalopodous Mollusca were not numerous, the predominating genera belonging to the Lamellibranchs and to the Gasteropods, which lived on the shore. The reef-making Madrepores or Corals were more numerous. A few Zoophytes in the fossil state testify to the existence of these extraordinary animals. The fossils characteristic of the fauna of the period include Ammonites decipiens and A. giganteus, Natica elegans and hemispherica, Ostrea deltoidea and O. virgula, Trigonia gibbosa, Pholadomya multicostata and P. acuticostata, Terebratula subsella, and Hemicidaris Purbeckensis. Some Fishes, Turtles, Paludina, Physa ([Fig. 123]), Unio, Planorbis ([Fig. 201]), and the little crustacean bivalves, the Cypris, constituted the fresh-water fauna of the period.
The terrestrial flora of the period consisted of Ferns, Cycadeaceæ, and Conifers; in the ponds and swamps some Zosteræ. The Zosteræ are monocotyledonous plants of the family of the Naïdaceæ, which grow in the sandy mud of maritime regions, forming there, with their long, narrow, and ribbon-like leaves, vast prairies of the most beautiful green. At low tides these masses of verdure appear somewhat exposed. They would form a retreat for a great number of marine animals, and afford nourishment to others.
XX.—Ideal Landscape of the Upper Oolitic Period.
On the opposite page an ideal landscape of the period ([Plate XX.]) represents some of the features of the Upper Oolite, especially the vegetation of the Jurassic period. The Sphenophyllum, among the Tree-ferns, is predominant in this vegetation; some Pandanas, a few Zamites, and many Conifers, but we perceive no Palms. A coral islet rises out of the sea, having somewhat of the form of the atolls of Oceania, indicating the importance these formations assumed in the Jurassic period. The animals represented are the Crocodileimus of Jourdan, the Ramphorynchus, with the imprints which characterise its footsteps, and some of the invertebrated animals of the period, as the Asteria, Comatula, Hemicidaris, Pteroceras. Aloft in the air floats the bird of Solenhofen, the Archæopteryx, which has been re-constructed from the skeleton, with the exception of the head, which remains undiscovered.