CXXXvi PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



be now written except upon entirely new localities ; and that smaller 

 papers fitted to fill np gaps in preceding descriptions, or to modify 

 and amplify some of the details upon which they were founded, should 

 now be more current. It is the result of the approximation to per- 

 fection in our science. 



We have had from Professor Owen, several papers during this ses- 

 sion, all tending to fill up the gaps in our knowledge of the verte- 

 brated animals of the ancient epochs of the Vvorld, or to complete the 

 history of those already known. The Stereognathus Ooliticiis had 

 been before named and described by Charlesworth ; and from the 

 fragm.ent of a lower jaw obtained from the Stonesfield slate by the 

 Rev. J. Dennis, and previously noticed at the British Association in 

 August last. Professor Owen was enabled to determine that the animal 

 is most probably a diminutive non-ruminant Artiodactyle, of carni- 

 vorous habits ; its nearest allied forms not being existing types, but 

 rather the Hyracotherium, JMicrotherium, and Hyopotamus of the 

 Tertiary deposits. He then explained the reasoning process, by which 

 such determnnations w^ere deduced from so small a fragment ; the mam- 

 malian character being determined by the two-fanged implantation 

 of the teeth, and the pachydermatous affinities by the peculiar sexcus- 

 pidate and cingulated molars, such structural peculiarities having been 

 before ascertained to exist in certain known Pachydermata. In this 

 case the Professor determined the natural position of the animal by 

 morphological resemblances or by structure, not by physiological con- 

 siderations or functional adaptation ; but the Professor observes, that, 

 though the paleeontologist must depend more frequently on the mor- 

 phological than on the physiological basis of reasoning in determining 

 the affinities of an animal, the physiological relations of which he 

 must so often be ignorant of, yet in many cases the analysis may be 

 safely made, from the manifest functional adaptation of the organ 

 examined. Let me add, that in any case, the result, in a philo- 

 sophical sense, must be imperfect until the physiological relations 

 have been discovered ; for until then, the animal must be considered a 

 mass of dead bones, like a crystal or other object of definite form, but 

 not an active member of the universe, destined to play its own part 

 in the scheme of animal existences. 



In another paper Professor Owen gives the detailed examination 

 of the tibia of the large fossil bird, from the Lower Eocene of Meudon 

 near Paris, named by Hebert Gastornis Parisiensis. Having care- 

 fully compared this bone with the corresponding bone in Binornis, 

 Noto7'nis, and the nearest related Orders of living birds. Professor 

 Owen concludes that the Gastornis was about the size of the Ostrich, 

 but comparatively slenderer, and that its nearest affinities are with 

 the Waders, and most probably Mith the Rallidse, but that the genus 

 is manifestly distinct from any living genus. Here again, in a de- 

 termination founded on morphological considerations, the important 

 fact to the student of the world's history is, that the bird was phy- 

 siologically a gigantic wader. 



Professor Owen next described a collection of mammalian fossils 

 from the lied Crag of Suffolk, including the Rhinoceros, of which 



