Mr. Yarrell on the occurence of some rare British Birds. 85 



This fossil, which Mr. G. B. Sowerby, (who was struck with 

 its general resemblance to my specimen of C. gutlala,) was kind 

 enough to send to me, was found in the Sujjerga, near Turin ? * 

 It appears to have suffered from pressure and fracture, which may 

 have added to the gibbosity of the back ; but still, thougli the 

 likeness is great, it does not appear to me to be identical with 

 C. guttata. The ventral disc of the latter, though corrugated as 

 strongly as that of C. rugosa at the extremities, is comparatively 

 smooth in the middle, and there the rugosities scarcely appear, 

 excepting towards the mouth of the shell, where they again be- 

 come strongly marked. The rugosities of the ventral disc of 

 C. rugosa furrow the whole of that disc, and are rather strongest 

 in the middle of it. With this exception, the rugcB on the disc, 

 lip and margins of both shells offer the strongest similarity. The 

 fossil appears much more gibbous than the recent shell above- 

 mentioned. 



Art. IX. On the occurrence of some rare British Birds. 

 Bi/ William Yarrell, Esq. F.L.S. 



[To the Conductors of the Zoological Journal.] 



Gentlemen, 

 Your liberal insertion of my former notice of the occurrence of 

 some rare British Birds, has induced me to forward you the follow- 

 ing particulars on the same subject, which I have been enabled to 

 collect within the last four months. 



Parus biarmicusy Linn. Two nests and the eggs of the 

 Bearded Tit were this year forwarded to London. They were 



• I judge this to be the fact, from having observed it to be filled with the 

 grains which so eminently characterize the fossils of that locality. The only 

 specimen 1 have seen I found among some fossils in the Collection of Mr. G. 

 Humphrey. The best account of this mountain and its formations is to be 

 found in Brongniart's Mem. sur leg Terrains de sediment superieurs calcareo- 

 trappeons du Vicentin. p. 27. He has not, however, noticed this species. 



G.B.S. 



