The Cretaceous Fauna of Poncloland. 315 



thought that the last was indistinguishable from S. ornata, but a 

 comparison of specimens shows that S. Dujnniana possesses more 

 inflated whorls, fewer transverse ribs, and coarser spiral ornamenta- 

 tion than S. ornata. 



Remark. — The type is in the Museum of the Geological Society. 

 The only other specimen seen is in the Survey Collection. 



Family SOLAEIID^. 



Genus SOLAEIUM, Lamarck. 



Solarium Bailyi, Gabb. 



Plate XXXVIII., figs. 4, 5. 



1855. Solarium pulcliellum, Baily, Q.J.G.S., xi., p. 457, pi. xii., 



fig. 3. 

 1871. Solarium Wieheli, Griesbach, Q.J.G.S., xxvii., p. 65, 



pi. iii., fig. 6. 

 1861. Solarium {Architectonica) Bailyi, Gabb, Proc. Amer. Phil. 

 Soc, vol. viii., p. 95. 

 Non 1850. Solarium 2)ulcheUum, d'Orbigny, Prodr. de Pal., ii., p. 104. 

 Description. — Shell small, depressed, conical, sometimes nearly 

 discoidal, consisting of five or six whorls with their upper surfaces 

 flattened. Last whorl larger than the one preceding. External 

 margin of shell rounded in fully-grown specimens, but thinner and 

 somewhat sharper in small examples. Base rounded. Umbilicus 

 small, with a diameter equal to a quarter or sometimes nearly a 

 third of that of the base. 



Upper surface of shell ornamented with numerous, narrow trans- 

 verse ribs extending across the whorls somewhat obliquely. These 

 ribs are strongest near the posterior suture, at a short distance from 

 which they become smaller and new ribs are intercalated, or, some- 

 times, the old ones bifurcate. These more numerous and smaller 

 ribs are continued on to the base of the shell, and become stronger 

 for some distance around the umbilicus, to the margin of which they 

 give a toothed appearance. The upper surface of the whorls is also 

 ornamented with spiral grooves separated by broad flat interspaces ; 

 the grooves are closer together near the margin of the whorls and 

 also on the base of the shell, but are absent where the transverse 

 ribs become stronger around the umbilicus. 



Length 7 . 6 . 5-5 . 3 mm. 



Breadth 12 .10 . 10-5 . 7-5 „ 



