232 ME. E. T. NEWTON" ON MESOZOIC FOSSILS [May IQOI, 



is from the zone of Ammonites anrjulatus, but our specimen is too 

 imperfect for definite identification. 



Pletjeotomaria tectaeia, Tate. (PI. IX, fig. 4.) 



1870. ' Irisli Liassic Fossils ' Rep. Belfast Nat. Field Club, App. i, p. 17. 

 1876. Tate & Blake, ' Yorkshire Lias ' p. 338 & pi. ix, fig. 26. 



A single specimen is referable to this species, but it is so like one 

 of Prof. Tate's type-specimens, now in the Museum of Practical 

 Geology, that I have no hesitation in referring it to the same 

 species, whicli was in the first place found in the Ammonites 

 angulatus-heds near Garron Point (Antrim), and afterwards recog- 

 nized by Messrs. Tate & Blake in beds of the same age at Eedcar 

 (Yorkshire). 



AvicuLA LANCEOLATA, Sowcrby. (PI. IX, fig. 5.) 



1826. ' Min. Conch.' pi. dxii, fig. 1. 



Nou^. lanceolata, Forbes, Quart. Jovirn. Geol. Soc. vol. i (1845) p. 247&pl. iii, fig. 8. 

 Non Gervillia lanceolata, Goldfuss, ' Petrefacta Germanise ' pt. ii (1834-40) p. 123 

 & pi. cxv, fig. 9. 



There are two or three internal casts of a shell which agree so 

 closely with Sowerby's Avicula lanceolata from the Lias of Lyme 

 llegis that I cannot do otherwise than refer them to the same 

 species. The most perfect specimen is a small one, 21 mm. long 

 and 3 1 mm. deep, including the wing at its widest part. It is 

 markedly straight and almost parallel-sided. The umbo is nearly 

 at the end of the shell. The cast of the straight hinge is marked 

 by two longitudinal grooves, the inner one being the deepest. The 

 posterior angle of the wing is rounded, and falls away backward with 

 a convex outline. The comparative length of this shell suggests its 

 reference to Gervillia ; but there are no indications of the ligament- 

 pits characteristic of that genus, and I am inclined therefore, for 

 the present, to let this shell remain in the genus Avicula. 



Prof. Tate, in his ' Irish Liassic Possils ' (p. 11), makes Sowerby's 

 A. lanceolata synonymous with Gervillia acuminata of Terqnem ^ ; 

 but with this identification I cannot agree ; the latter species is a 

 proportionately deeper shell, and much more curved. 



Pecten (Chlamys) stjbulatus (?) Goldfuss. (PI. IX, fig. 6.) 

 1834-40. ' Petrefacta Germanise ' pt. ii, p. 73 & pi. xcviii, fig. 12. 



Several internal casts of a smooth Pecten are provisionally placed 

 in this species, as they seem most nearly to agree with Goldfuss's 

 figures and description. Two of these are impressions of right 

 valv^es, and show the shell to have been orbicular but somewhat 

 oblique. The anterior wing of the right valve is large, with a 

 deep byssal notch and a strongly crenulated ligamental margin. 

 Below the wing the anterior margin of the shell is deeply concave. 

 The nmbo is acute and the posterior wing small. Specimens from 

 the Ammonites angidatus-heds of Down Hatherley, which agree 

 very closely with the Arran specimens, are in the Tate Collection, 

 preserved in the Museum of Practical Geology. I am unable to 



1 ' Paleont. de la Province de Luxembourg & de Hettange ' Mem. Soc. G-eol, 

 France, ser. 2, vol. v (1855) p. 316 & pi. xxi, fig. 15. 



