264 E. T. Neicton—The "Tunny " in the Forest Bed Series. 



VI. — Note on the Occurrence of the Tunny (Thynnus thynnus) 

 in the Cromer " Forest Bed." 



By E. T. Newton, F.G.S., F.Z.S. 



ME. E. Storms has recently described (Bull. Soc. Beige Geol. 

 vol. iii. p. 163, 1889) the vertebras of a large Tunny from the 

 Antwerp Crag, which he has named Thynnvs Scaklesii, and Mr. A. 

 Smith Woodward, in the April number of the Annals and Maga- 

 zine of Natural History, records the same species from the Coralline 

 Crag of Suffolk ; it is especially interesting, therefore, to be able at 

 this time to notice the occurrence of the common Tunny (T. thynnus) 

 in the Cromer " Forest Bed." 



Early in the present year, Mr. A. Savin, of Cromer, found in the 

 "Forest Bed" of East Eunton a large Teleostean fish-vertebra, 

 which he sent to me for identification, and which agreed so closely 

 in all its characters with the nineteenth vertebra of the large Tunny 

 in the Museum of the Eoyal College of Surgeons, that I had no 

 hesitation in referring it to the same species. This vertebra has lost 

 all its processes, but the centrum now measures 43 mm. long, 53mm. 

 wide, and 45mm. high; it is deeply biconcave and somewhat 

 depressed ; it is further characterized by a single large longitudinal 

 bar on each side, which thickens anteriorly and posteriorly, a 

 roughened space towards its front part indicating the point of 

 attachment of the rib. Above and below the bar is a deep fossa. 



The nineteenth vertebra of the Tunny in the College of' Surgeons 

 measures 49 - 5mm. long, and 60 - 5mm. wide, a proportion of length 

 to width almost exactly that of the Forest Bed specimen. 



It was intended to reserve the notice of this species for a forth- 

 coming memoir of the Geological Survey, but the publication of Mr. 

 Smith Woodward's account of the Coralline Crag T. Scaldesiensis 

 seemed a fitting opportunity to make known the occurrence of the 

 recent species in the uppermost beds of the English Pliocene. After 

 a re-examination and comparison of the Forest Bed vertebra with 

 the recent form, and also of the Antwerp and Coralline Crag 

 specimens, I am quite of opinion that the Crag fossils are specifically 

 distinct from the living Thynnus thynnus, but am confirmed in my 

 identification of the " Forest Bed " vertebra with the latter species. 



VII. — Notes on the Probable Origin of Some Slates. 

 By W. Maynahd Hutchings. 



ME. SOEBY, in his Address as President of the Eoyal Micro- 

 scopical Society in 1877, dwelt very forcibly on the interest 

 and value attaching to researches into the original nature of the 

 materials composing sedimentary deposits, and stated that, so far as 

 he was aware, but little had been done in this direction by means of 

 the microscope (Monthly Microscop. Journal, vol. xvii.). 



Since Mr. Sorby delivered that address much has been done in 

 this direction, both by workers in this country and on the Continent, 

 and more especially with regard to slates and allied rocks. But 



