Geological Society. 61 



iridescence, times of appearance, and diffusion round the coast, 

 formed the principal topics embraced in the remainder of the paper. 

 The occurrence of the Bolina on different parts of the Irish coast 

 was mentioned, principally for the purpose of enabling Mr. Patterson 

 to refer to some points of its ceconomy for comparison and contrast 

 with the C. pomiformis . He reserved a detailed account of various 

 particulars concerning it to a future opportunity, when he expected 

 to be able to exhibit additional figures taken from living specimens, 

 and more accurately delineated than those at present brought for- 

 ward. Meantime, as the animal differed from the two species of 

 Bolina described by Mutius, he proposed to name it provisionally 

 Bolina Hibernica. 



GEOLOGICAL SOCIETY. 



Nov. 21, 1838. — A paper was read " On the Jaws of the Thyla- 

 cotherium Prevostii* (Valenciennes) from Stonesfield," by Richard 

 Owen, Esq., F.G.S., Hunterian Professor, Royal College of Sur- 

 geons. 



Doubts having been recently expressed by M. de Blainvillef, from 

 inspection of casts, respecting the mammiferous nature of the fossil 

 jaws found at Stonesfield, and assigned to the Marsupialia by Baron 

 Cuvier, Mr, Owen brought the paper before the Society, to meet the 

 objections and give a detailed account of the fossils from a careful 

 inspection of the originals. In this communication, however, he 

 confined his description chiefly to the jaws of one of the two genera 

 which have been discovered at Stonesfield, and characterized by 

 having eleven molars in each ramus of the lower jaw, reserving to a 

 future occasion an account of the remains of the other genusj. 



Mr. Owen commences by observing that the scientific world pos- 

 sesses ample experience of the truth and tact with which the illus- 

 trious Cuvier formed his judgements of the affinities of an extinct 

 animal from the inspection of a fossil fragment ; and that it is only 

 when so distinguished a comparative anatomist as M. de Blainville 

 questions the determinations, that it becomes the duty of those who 

 possess the means to investigate the nature of the doubts, and re- 

 assure the confidence of geologists in their great guide. 



When Cuvier first hastily examined at Oxford, in 1818, one of 



* Comptes Rendus, 1838 ; Second Semestre, No. 11, Sept. 10, p. 580. 



t Ibid., No. 8, Aout 20, p. 402 et seq.; No. 9, Planche ; No. 17. 

 Oct. 22, p. 727 ; No. 18, Oct. 29, p. 750. 



X This has since been read, and an abstract of it will appear in one of 

 our next numbers. — Edit. 



