MESOZOIC TIME — TRIASSIC AND JURASSIC. 791 



florigemma, C. BlumenhacMi, Apiocrinus Meriani. (b) Pterocprian, -with Amm. acanthi- 

 cus, Pterocera oceani, P. ponti, Nerinea depressa^ Waldheimia humeralis. (c) Virgulian, 

 with Gryphcea virgula, Trigonia gihhosa, Terebratula diphya, Pholadomya muUicostata, 

 Thracia depressa. (d) Bolonian, with Amm. gigas, A. suprajurensis, A. biplex, Trigonia 

 incurva, Cyprina Brongniarti. 



(2) Portlandian or Tithonian. (a) Portlandian or Nerinean, Amm. gigas, Trigonia 

 gibbosa, Gryphcea virgula, Ostrea solitaria, Lucina Portlandica, Nerinea trinodosa, 

 Pterocera oceani. (6) Purbeckian, with Corbula inflexa, C. Forbesiana, Cardium 

 Purbeckense, Terebratula diphyoides, Hemicidaris Purbeckensis, Astrxa distorta. Insects, 

 Mammals. 



The Tithonian group in the eastern Alps includes a coral limestone near Salzkammer- 

 gut, and the Diphya limestone abounding in Terebratula diphya ; also Aptychus beds ; 

 and some of the limestones contain many Ammonites, Phylloceras ptychoicum, and others. 



The Jurassic beds of Cutch, in India, contain, in the Lower Oolyte, Astarte com- 

 pressa, Corbula pectinata, Bhynchonella concinna; in the Middle Oolyte, Amm. (Stepha- 

 noceras) macrocephalus, A. (Peltoceras) athleta, Terebratula biplieata, T. sella, and 

 many other Ammonites, many Belemnites, etc. ; in the Upper Oolyte, Amm. (Phylloceras) 

 ptychoicus, and many other species. Also many species of plants, as Sphenop)teris arguta, 

 Alethopteris miitbyensis, Otozamites contiguus. The Portlandian beds afford Trigonia 

 Smeei and T. ventricosa, the latter also a South African species ; also jaw of a Plesiosaur. 



The Upper Jurassic of the Zanskar area in the central Himalayas has afforded 

 Belemnites clavatus, Ammonites macrocephalus, A. Parkinsoni, A. biplex, Trigonia 

 costata, and other species. The Hundes area in the Tibetan Himalayas also has many 

 Jurassic species. (Cf. Medlicott and Blandford, Geology of India, vols. i. and ii., 1879, 

 and second edition by Oldham, 1894.) 



In western Australia, 20 species of Liassic and Oolytic fossils are identical with 

 British species : 3 of the Ammonite group. Nautilus semistriatus and Gresslya donaci- 

 formis of the Upper Lias ; Myacites Liassinus of the Middle Lias ; and 2 of the Ammonite 

 group, with Belemnites canaliculatus, Cuculloia oblonga, Pholadomya ovulum, Avicula 

 Munsteri, A. echinata, Pecten cinctus, P. calvus, Lima proboscidea, L. punctata, Ostrea 

 Marsha, Bhynchonella variabilis, Cristellaria cultrata, of the Oolyte (C. Moore). 



CONTINENTAL RESEMBLANCES AND CONTRASTS IN THE TRIASSIC AND JURAS- 

 SIC PERIODS; CLIMATE. 



The Triassic formation is alike over a large part of Europe and America in 

 kinds of rocks, in paucity of fossils, and in evidences of shallow-water origin, 

 and of largely brackish water, if not fresh. The continental surface in each 

 case was very near or above the water level over large areas ; and it 

 oscillated between brackish or fresh-water flats and barren or half-barren 

 salt-water flats or sea-border salt-pans. The European exception is in the 

 Mediterranean region. Not only is this general fact true for the two conti- 

 nents mentioned, but also for India, South Africa, and Australia, or the 

 continental regions in the opposite hemisphere. This so general prevalence 

 over large parts of the continents of slight submergence, too slight for abun- 

 dant remains of marine life, — although this life must undoubtedly have 

 been as profuse in kinds as in any earlier or later era, — indicates general 

 and synchronous movements in the earth's surface, and correlate progress 

 in continental growth. The Jurassic period was, in contrast, a period of 

 somewhat deeper and clearer seas, sustaining at many levels abundant life, 



