417 



A. subcarinatus, A. angulatus, A. crassus, A.Jibulatus, A. subarmatus, 

 A. Lythensis, A. Boulbiensis, A. annulatus, Nautilus astacoides, and 

 Belemnites elongatus. The species gradually decrease in abundance 

 on approaching the jet rock, and the specimens which do occur in 

 that stratum are stated to be smaller than in the higher beds. The 

 jet rock contains a peculiar suite of Ammonites, viz. A. elegans, A. sig- 

 nifer, A. elegantuliis, A. exaratus, A. Mulgravius, A. concavus, and 

 A. ovatus. It is also distinguished by containing the remains of the 

 gavial-snouted crocodile. With respect to the relative abundance of 

 the fossils, Mr. Hunter observes that where they occur in the greatest 

 number they are smallest in size. 



The beds situated between the jet rock and the marlstone are very 

 poor in fossils. 



The marlstone series is distinguished not only by a change in the 

 species, but in the preponderance of bivalves and the comparative ra- 

 rity of Ammonites j the characteristic fossils being Avicula cygnipes, 

 A. incequivalvis, Pecten suhlcEvis, P. (equivalvis, Pullastra antiqua, se- 

 veral species of Terebratula, Cardium truncatum, Modiola scalprum. 

 The species of Ammonites are few, A. vittatus occurring about the 

 centre of the series, and A. maculatus at the junction with the lower 

 lias shale. 



In conclusion, Mr. Hunter states that the difference between the 

 distribution assigned to the fossils by himself and other authors may 

 be owing to the prevalent practice of collecting fossils from subsided 

 masses, and not from undisturbed portions of the cliffs. 



A letter was, lastly, read from Robert Fitch, Esq., of Norwich, to 

 Edward Charlesworth, Esq., F.G.S., on the discovery of the Tooth of a 

 Mastodon in the crag at Thorpe, near Norwich. 



The pit in which the tooth was found is stated to present the fol- 

 lowing section : 



Top. Alluvium 5 feet 



Gravel 6 



Brick-earth, sand, and gravel 14 



Crag 5 



Large chalk flints, mixed with crag shells, 



principally Pectens 



Chalk 



It was in the bed of large chalk flints that Mr. Fitch found the 

 tooth ; and he adds that Thorpe adjoins the parish of Whitlingham, 

 in which Mr. William Smith discovered the tooth figured in his " Strata 

 Identified." 



June 8. — Henry Hubert, Esq., F.R.A.S. of New Bridge- street, 

 Blackfriars ; the Hon. William Lascelles, of Wilton-crescent ; the 

 Hon. W. Bingham Baring, M.P., of Great Stanhope-street j the 

 Hon. John Stewart Wortley, of Curzon-street, May Fair j and the 

 Right Hon. Baron James Parke, of Park-street, were elected Fellows 

 of this Society. 



2f 



