proceedings of the cotteswold club 253 

 Communis Zone 



Additional note on the gasteropod, Euomphalus minutus 

 (Zieten.) 



As this minute fossil has been often a subject of mis- 

 apprehension, it will be well to draw attention to its 

 lineage. The geodes of the " Insect Limestone " course 

 (Communis Zone) Upper Lias are often profusely studded 

 with this tiny fossil, in flict, the whole of the blanched, 

 weather-worn surfaces of the limestone seem to be covered 

 with dark beads, more or less perfect; which, under a simple 

 field lens, one might fancy were Liliputian Ammonites. 

 This gasteropod is the Euomphalus minutus of Zieten, 

 referred to by Quensted as a species of Natica. (See 

 Jura, page 262). I'hey were noticed also by Professor 

 Tate, who believed he had met with a new species, and 

 described it in the " Geological Magazine," vol. viii, page 

 8, 187 1, as follows: — "Natica pilula, nov. sp. Very 

 small, globose, spire depressed, slightly convex, whorls 4 

 to 5, ornamented with fine longitudinal lines, aperture 

 narrow. Upper Lias, Dumbleton." I would add to 

 " Dumbleton," " Gretton," since specimens have been 

 found there by a member of the Cotteswold Club, as well 

 as in the same zone at Churchdown. The fact is, these small 

 gasteropods were first named Euomphalus minutus by 

 Zieten in 1833, then it became the Natica puUa of Romer 

 in 1839, followed by Tate's synonym of Natica pilula in 

 187 1, and it could be traced onwards if it were worth 

 while. The utility of extending our acquaintance with the 

 gasteropods of the Lias is now acknowledged, and not too 

 soon, by the monograph on the subject issued by the 

 Palseontographical Society of London, which is now in 

 course of publication. 



The interesting character of our Lepta;na Clays which 

 lie above the top Zone of the Middle Lias, next to be 

 treated, induces me to quote the following remarks of Mr 

 Moore, F.G.S., referring to analogous beds.* 



Proc. Somerset Arch, and Nat. Hist. Soc. Vol. xiii, pp. 130, 132. 



