1890.] NATURAL SCIKNCK.S OF PHILADELPHIA. 453 



no other form that approaches it. Zittel refers both species to the 

 genus Remondia.^ 



Chemnitzia zebra. 



This species is poorly drawn. The spire broadens out consider- 

 ably more than is represented in the figure (pi. 35, fig. 5), and the 

 whorls are almost flat-sided. 



Anchura monilifera. 



The figure-measure (pi. 35, fig. 7) is considerably larger than the 

 specimen actually figured, and it exceeds by about one-sixth the lar- 

 gest specimen in the collection. 



Euspira tabulata. 



Gabb states that this species " looks much more like a Jurassic 

 than like a Cretaceous species" (p. 260). I cannot concur in this 

 opinion. The Academy collections contain specimens of Natlca sub- 

 bulbijorinis D'Orb., from the Cretaceous deposits (Turonian) of 

 Uchaux, France, which are barely distinguishable from the Mexi- 

 can form. 



Natica Pedernalis, as it is represented on Plate 35, fig. 3, does not 

 exist. The figure is compounded from two fossils, which have little 

 in common with one another, and seemingly represent two distinct 

 genera. . The specimen which gives the outline to the drawing is 

 very imperfect and shows no trace of an umbilicus. I doubt much 

 if it is even a member of the Naticidoe.. The second form is a true 

 Natica, which may or may not be Roemer's N. Pedernalis, the type 

 cast of which does not permit of the identification of the species. 

 The Mexican specimen, although somewhat distorted, is perfectly 

 preserved, and I cannot understand how Gabb could have con- 

 founded it with the form which he erroneously describes and figures 

 as Natica Pedernalis. 



Neither the material published by Gabb, nor the somewhat more 

 extended note on the formation which is furnished by Remond,^ is 

 suflBcient to allow us to state positively whether the deposits in 

 question are absolutely synchronous with those of Jalapa and 

 Tehuacan or not. Probably they represent a somewhat lower stage 

 of the Cretaceous and are the quivalent of a portion of the Ceno- 

 manian. By Dr. White the beds are correlated with the Comanche 



1 Handbuch der Palseonlologie, II, p. 58. 



* Notice of Geological Explorations in Northern Mexico — Proc. California 

 Acad. Nat. Sci. Ill, pp. 5 and 11, 1866. 



