464 



MESOZOIC TIME — REPTILIAN AGE. 



genera Cyrena, Planorbis, Limnsea, Unio, and Paludina. 

 densis ; 744, Vivipara (Paludina) Flnviorum. 



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, Cicadas, 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- 

 ihyosaur and Plesiosaur ; Dinosaurs of the genera 

 Iguanodon, Hylseosaur, Megalosaur, Regnosaur ; 

 fig. 745, tooth of the Iguanodon; Crocodilians 

 with biconcave vertebras of the genera Suchosaur, 

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

 cave vertebrae of the genus Cetiosaur, and also the 

 first of the concavo-convex, or proccelian, in species 

 of the modern genus Crocodilus ; Pterodactyls ; 

 Turtles, as the Tretosternum punctatum Owen ( Tri- 

 onyx Bakewelli Mantell), etc. 



Fig. 743, Unit* VaU 

 Fig. 745. 



Iguanodon Mantelli. 



Fossils characteristic of the Subdivisions of the Jurassic. 



1. Lower Lias. — Diadema seriale (fig. 694); Pentacrinua Briareus ; Spiri- 

 ferina Walcotti (fig. 697); Gryphcea arcuata (fig. 699); Gardinia coneinna; Cte- 

 noides (Plagiostoma) gigantea ; Pleurotomaria Anglica ; Ammonites bisulcatus (or 

 Bucklandi) (fig. 701), A. Planorbis, A. Gonybeari, A. Nodotianus (fig. 700); Be- 

 lemnites acutus ; Tetragonolepis ; Plesiosaurus, Pterodactylus macronyx. 



2. Middle Lias. — Terebratida rimosa, T. numismalis, Gryphcea Cymbium, Pec- 

 ten &quivalvis, Pleurotomaria expansa, Ammonites margaritatus, A. spinatus, Be- 

 lemnites clavatus, B. paxillosus (fig. 704). 



3. Upper Lias. — Pentacrinus vidgaris ; Leptcena Moorei, etc. ; Ostrea Knorri .• 

 Posidonia Bronnii, Turbo subplieatus ; Ammonites bifrons, A. heterophyllus, A. 

 radians (Rein.), A. serpentinus, Belemnites irregularis, Geotenthis Bollensis, Teu- 

 dopsis Schiebleri. 



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

 Rhynchonella spinosa, T. fimbria, T. pcrovalis, Rhynchonella spinosa ; Ostret* 

 Marshii, 0. acuminata, Pecten Lens, Trigonia costata, Pholadomyi ""idicnla ; 

 Turbo ornatu8, Pleurotomaria granulata ; Ammonites Humphrey sianus (fig. 730), 

 A. Parhinsoni, A. Braikenridgii, Nautilus lineatus, Belemnites giganteus. 



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

 Marble). — Apioctinus Parhinsoni, A. elegans, Clypeus Patella ; Terebratida digo- 

 na, Ostrea acuminata, Pecten Lens, P. vagans, Pholadomya gibbosa, Trigonia cos- 

 tata ; Pnrpuroidea nodulata, Cylindrites acutus; Ammonites Discus, A. bullattts, 

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

 tiosaur, Pterodactyls, etc. 



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



