Geological Society. 691 
=17 mm.; diameter of the largest column =15 mm.; diameter 
of small column=10 mm. This tooth is considerably worn. 
The second tooth was found in the same locality last year by 
the Rey. Robert Connell. Its dimensions are: Length =47 mm.; 
width =34 mm.; diameter of the largest column=24 mm.; dia- 
meter of the smallest column =17 mm. 
The following communication was read :— 
‘On the Geological Importance of the Primitive Reptilian Fauna 
in the Upper Cretaceous of Hungary.’ By Baron Francis Nopesa, 
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 Cenomanian, 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 brackish-water beds gradually into 
the marine strata. 
The age of these marine deposits has been well established by 
different fossils (mostly 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 Plewro- 
sternum, a Camptosaurian Dinosaur (2habdodon), a remarkably 
primitive Trachodon (Orthomerus), a Sauropodous Dinosaur 
( Titanosaurus) that is generically identical with a Wealden type, 
an armoured Dinosaur (Struthiosaurus) 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 (Dinosaurs) 
but did not affect the smaller forms (crocodiles and tortoises). 
In consequence of a general uplift at the dawn of the Kocene 
and the cooling of the climate, nearly the whole of this fauna 
became extinct, the different changes brought about by these two 
factors 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. 
