CRETACEOUS. 353 



proposed by Jules Thurmann about the year 1832 (mainly through the labours of 

 Auguste de Montmollin) for certain strata which are developed near Neuchatel 

 (Neocomum) in Switzerland, and correspond in age with our Wealden Beds. In 

 this country, however, the term has been used to embrace not only the Wealden, 

 but also the Lower Greensand ; while latterly some authorities have been disposed 

 to restrict the name Neocomian to the Lower Greensand, or to those strata that 

 occur above the Wealden and below the Gault ! Moreover, on the Continent, 

 Neocomian has been applied in different senses ;^ hence on the whole it is a very 

 unfortunate term. 



The organic remains of the Cretaceous Rocks inchide among 

 Plants, remains of Fuci, Coniferae, and Cycadaceae ; also many 

 Sponges and Foraminifera. Corals are not abundant, and, as 

 Dr. Duncan remarks, " There are no traces of any Coral reefs 

 or atolls in the British Cretaceous area, and its Corals were of 

 a kind whose representatives for the most part live at a depth 

 of from five to six hundred fathoms." ^ The Echinoderms are 

 conspicuous among Cretaceous fossils, and include Sa/cina, 

 Diadeina, Mtcraster, Holaster, etc. Among the Annelides we 

 find Vennicnlana, and the Crustacea comprise Cirripedes, 

 Ostracoda, and Podophthalmia. The Brachiopoda include 

 Crania and other forms ; the Mollusca are well represented 

 by the Lamellibranchiata, Ostrea, Pecteii, Inoceraiinis, Area, 

 Pectnucuhis, etc., while the Gasteropoda include forms like 

 Aporrhais, T2irritella, Solarium, Scalaria, etc., which fore- 

 shadow Tertiary life. Of Cephalopoda there are species 

 of Ammonites, TiuTilites, ScapJiites, Hamites, and Baenlites, 

 also Belemnites and Belemnitella (found in the Chalk). The 

 Vertebrata include many Fishes, Lamna, Otodus, PtycJiodus, 

 Beryx, Ischyodus, etc. Among the Saurians we find the 

 Lacertilian genus JMosasaurns (essentially Cretaceous), so 

 that the term Mosasaurian was applied to the system by 

 John Phillips. Dinosaurians and Chelonians are also con- 

 spicuous forms. Birds, including Enaliornis and Pelagornis, 

 have been found in the Cambridge "Greensand"; and another 

 genus Palcwrnis has been obtained from the Wealden Beds. 

 No Mammals have been recorded from Cretaceous rocks in 

 this country.^ 



The divisional line between the Cretaceous and Jurassic systems, 

 like that taken between some other systems, is one of convenience, 

 and not one indicating any great physical break, for the Wealden 

 and Purbeck Beds are intimately connected. The Purbeck Beds 

 mark the commencement of those freshwater conditions which 



^ A. J. Jukes-Browne, G. Mag. 1SS6, p. 311 ; see also Judd, Ibid. 1870, p. 225, 

 1886, p. 382. 



' Duncan, Supp. to Brit. Fossil Corals (Palceontogr. Soc), Part IL No. 2, 

 1870. 



^ See woi^ks by Owen, Sharpe, Davidson, and others (Palseontograph. Soc.) ; 

 also A. D. D'Orbigny, Paleontol. Francaise, Terrain Cretace. 



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