464 



MESOZOIC TIME — REPTILIAN AGE. 



Fig. 745. 



genera Cyrena, Planorbis, Lhnnsea, Unio, and Paludina. Fig. 743, Unio Val- 

 densis ; 744, Vivipara (Paludina) Fluviorum. 



3. Articulates. — Ostracoids, related to Cy- 

 pris, etc., very abundant in some layers. Insects 

 of thirty or forty families, including Coleopters, 

 Orthopters, Neuropters, Hemipters, and Dipters, 

 or Beetles, Crickets, Dragon-flies, Cicadse, May- 

 flies, etc. 



4. Vertebrates. — Fishes of the orders of Ga- 

 noids and Selachians, in all thirty or forty spe- 

 cies. Reptiles. — Enaliosaurs of the genera Ich- 

 thyosaur and Plcsiosaur; Dinosaurs of the genera 

 Iguanodon, Hylscosaur, Megalosaur, Regnosaur ; 

 fig. 745, tooth of the Iguanodon; Crocodilians 

 with biconcave vertebra of the genera Suchosaur, 

 Goniopholis, Pcccilopleuron, etc., with convexo-con- 

 cave vertebras of the genus Cetiosaur, but none of 

 the modern or procoelian type (concavo-convex), 

 which appear first in the Cretaceous ; Pterodactyls ; 

 Turtles, as the Tretosternum punctatum Owen (Tri- 



onyx Bakewelli Mantell), etc. 



Iguanodon Mantelh. 



Fossils characteristic of the Subdivisions of the Jurassic. 



1. Lower Lias. — Diadema seriale (fig. 694); Spiriferina Walcotti (fig. 697); 

 Gryphsea arcuata (fig. 699); Cardinia concinna ; Pleurotomaria Anglica ; Am- 

 monites bisulcatus (or Bucklandi) (fig. 701), A. catenatus, A. Conybeari, A. No- 

 dotianus (fig. 700); Belemnites acutus. 



2. Middle Lias. — Pentacrinus Briareus ; Terebratula rimosa, T. numismalis, 

 Gryp>hsea Cymbium, Pecten sequivalvis, Pleurotomaria exjiansa, Ammonites marga- 

 ritatus, A. spinatus, Belemnites niger, B. paxillosus (fig. 704). 



3. Upper Lias. — Pentacrinus vulgaris ; Leptsena Moorei, etc.; Ostrea Knorri ; 

 Posidonia Bronnii, Ctenoides (Plagiostoma) gigantea, Turbo subjilicatus; Am- 

 monites bifrons, A. heterop>hyllus, A. radians (Rein.), A. serpentinus, A. Braiken- 

 ridgii, Belemnites irregularis. 



4. Lower Oolite. — (1.) Inferior Oolite. — Dysaster ringens, Clypeus Hugi ; 

 Terebratula sjtinosa, T. fimbria, T. i^rovalis, Rhynchonella spinosa; Ostrea 

 Marshii, 0. acuminata, Pecten Lens, Ctenoides gigantea, Trigonia costata, Phola- 

 domya Fidicula ; Turbo gibbosus, Pleurotomaria granulata ; Ammonites Hump>hrey- 



'sianus (fig. 730), A. striatulus, A. Braikenridgii, Nautilus lineatus, Belemnites 

 giganteus. 



(2.) Great Oolite (Bath Oolite, including Stonesfield slate, Cornbrash and Forest 

 Marble). — Apiocrinus rotundus, A. Parkinsoni, A. elegans, Clypeus Patella; 

 Terebratula digona, Ostrea acuminata, Pecten Lens, Pholadomya gibbosa, Trigonia 

 costata ; Purpuroidea nodulata, Cylindrites acutus ; Ammonites Discus, A. bidlatus, 

 A. Braikenridgii, Belemnites giganteus ; Megalosaurus Bucklandi, Teleosaur, Ce- 

 tiosaur, Pterodactyls, etc. 



5. Middle Oolite. — (1.) Oxford Clay and Kelloway Rock. — Dysaster canali- 



