Geological Society, T)'.)! 



= 17 mill.; (liuiiu'tcr nf llio lart^pst c(tluinii = 1 ■') imii. ; iluiini'lei' 

 (»f siiiiiU c'oluiiiii = 10 mm. 'I'liis luotli is coiisidcraMy worn, 

 'riu' second tooth was found in tlio saint' locality last year by 

 the iii'V. Holiert t'oniiell. Its dimensions are : Length =^ 17 nmi.; 

 width = ;}!• mm.; diainet4.T of the largest column = 2 !• mm.; dia- 

 meter of the smallest (•(damn = 17 mm. 



The followini; cnmmunieation was read: — 



'On the Geolo>i;ical [mportance of the Primitive Keptiliaii Kaiina 

 in the Upper Cretaceous of Hungary.' IJy Haron Francis N(jpesa, 

 For.Corresp.G.S. 



The Upper Cretaceous of Eastern Hungary can be divided into 

 two horizons, with an unconformity between them. The lower 

 niveau comprises the Conomanian, Turonian, and Lower Senonian 

 strata, the upper one the uppermost Senonian and the Danian 

 formation. 



While the entire lower horizon and the Upper Senonian rocks 

 are of marine origin, the Danian is a freshwater deposit that 

 passes downwards by means of braekish-water beds gradujilly into 

 the marine strata. 



The age of these marine deposits has been well established by 

 different fossils (mosth' ammonites) ; the age of the remarkably- 

 thick freshwater beds is partly determined by their position 

 between the older Maastrichtian and the younger Middle Eocene 

 strata, partly by rolled material containing fossils. 



The vertebrate fauna of the freshwater beds has, despite its 

 Upper Cretaceous age, a strikingly Jurassic aspect, for one finds 

 primitive tortoises (among them a new genus) related to Pleitro- 

 sternum, a Camptosaurian J)inosaur (Hhabilodon), a remarkablv 

 j)rimitive Trachodon (OrtJiomeri/s), a Sauropodous Dinosaur 

 {Titanosaiinis) that is generically identical with a Wealden tv2:>e, 

 an armoured Dinosaur {Striithiosaio-us) showing still a condyle 

 directed downwards, and a Pterosaurian related to the Wealden 

 Ornithodesmus. 



The survival of this fauna is explained by the fact that, during 

 the whole of the Cretaceous Period, it was isolated. This Isola- 

 tion brought about a dwarfing of the larger animals (l)inosaurs) 

 but did not affect the smaller forms (crocodiles and tortoises). 



In consequence of a general ui)lift at the dawn of the Eocene 

 and the cooling of the climate, nearly the whole of this fauna 

 became extinct, the different changes brought about b}' these two 

 factoi-s acting differently upon the different members of the 

 fauna. 



The terrestrial Dinosaurs were compelled to give place to the 

 more agile mammals, the herbivorous Dinosaurs of the marshy 

 tracts suffered from the change of the flora, while the warm- 

 blooded Pterosaurians became extinct, on account of the cooling 

 of the climate. 



