MIOCENE MOLLUSCA OF LAKE URMI. 443 



the remaining specimens are considerably water-worn, having 

 been obtained from the beach at the island of Koyun Daghi. 

 formation. Miocene (Helvetian). 



Pecten (Amussiopecten) like Burdig-ale]S"sis, LamarcTc. 



Pecten Burcligalensis, Lamarck, Annales du Museum, 1809, vol. viii. 

 p. 356 ; Goldfuss, Petrefacta Germanise, 1833, vol. ii, pi. 96. fig. 9, pp. 66, 

 80 ; Abich, Mem. Ac. Imp. Sci. St. Petersbourg, 1858, vol. vii. p.|120 

 (62) ; Homes, Abhandl. k.-k. Gaol. Reicbs. 1867, vol. iv. pi. 65, p., ,418. 



Amussiojjecten Burdigalensis, Sacco, Moil. Terz. Piemonte, &c., 1897, 

 pt. 24, pi. 15. figs. 1-7, p. 53. 



Pecten {Amussiojyecten) Burdigalensis, R. B. Newton, Geol. Mag. 1899, 

 p. 209. 



This form is represented by a very much worn specimen, with 

 rather imperfect margins. It shows wide and slightly raised costfe ; 

 and the surface is covered with numerous obsolete concentric 

 striatioDS. Dr. Fuchs' Persian shell from the Siokuh mountain, 

 P. j^lacenta^ appears to be closely related to it (Deukschr. K. 

 Akad. Wiss. 1879, vol. xli. pi. 2, figs. 1,2, p. 104). 



The true Burcligalensis is a well-known Miocene species, being 

 found in both the Helvetian and Burdigalian divisions of that 

 period, and it forms the type of Sacco's sub-genus Amussiopecten. 



Locality. Prom the beach of the island of Koyun Daghi. 



Formation. Miocene (Helvetian ?). 



Pecten (Oopecten) eotundatus, Lamarck. (Plate 29. fig. 1.) 



Pecten rottindatus, Lamarck, Hist. Nat. Anim. sans Vert. 1819, vol. vi. 

 pt. 1, p. 179 ; T. Fucks, Denksckr. K. Akad. Wiss. 1879, vol. xli. pt. 2, 

 pi. 2. figs. 1, 2, p. 104; Fontannes, Hist. Periode Tert. Rhone, 1880, 

 vol vi. pi. 1, fig. 1, p. 161, 



Oopecten rotundatus, Sacco, Moll. Terz. Piemonte, &c., 1897, pt. 24, 

 pi. 15. figs. 14, 15, p. 54. 



Original specific description : — " P. testa suhorhiculari, utrin- 

 que conveoca ; radiis 14 ad 16 distinctis, conveocis, versus limbum 

 planulatis. 



" Largeur 75 millimetres. II est moins bombe que le P. multi- 

 radiatus et que le P. rugosus.^^ (Lamarck.) 



A small block of a light brown calcareous sandstone obtained 

 from a conglomerate contains remains of this species ; the best 

 preserved valve having a height of 60 millimetres and a length of 

 rather more than 70 millim. 



It agrees with the original diagnosis as given above, and 

 corresponds with Dr. T. Puchs' later interpretation of the same, 



