1890.] NATUKAF, SCIKNCES OF PIIILADKLPHIA. 447 



blue limestones, which he h>cates as follows: — of Songuantla, at the 

 elevated base of the ( !ofre de Perote, two and a half leagues from 

 Jalapa ; the barranca (ravine) of Gilotepec, 4 leagues N. N. E. 

 of Jalapa ; the hacienda of Tusaniapa ; the barranca of Jalcomulco, 

 S. S. E. of Jalapa. These various outcrops, which in a general 

 way are said to trend W. N. W.— E. S. E. or W. by N.— E. by S., 

 with a steep pitch southward or southwestward, are on paleon- 

 tological grounds referred to a single horizon, which is considered 

 to be the partial equivalent of Dufrenoy's Cretaceous of southern 

 France. This determination rests on the discovery in the rocks of 

 fragments oi' Ammonites, Ostrea, Pecten, Cardium and Lucina, and 

 of various foraminiferal forms (3£iliola, Nodosaria, Nummulina). 



I strongly suspect that what are here referred to as fragments of 

 oysters are in part, at least, the remains of Hippiiritidce. These are 

 abundant in the limestone of Coatepec, of the same region, which I 

 examined, but I failed to find in that rock any true oysters; how- 

 ever, this is only negative testimony. The Hippuritida? there occur- 

 ring are sufficient evidence of the correctness of Galeotti's reference. 

 Less reliable, probably, is Galeotti's determination of his assumed 

 Nummulite, which he describes as Nujnviulina Song^iantlw (p. 85.) 

 No undoubted member of this group of organisms has thus far been 

 found in any Cretaceous deposit, and it is likely that the present re- 

 ference rests on an erroneous interpretation of the fossil in question. 

 Galeotti's figure (Bulletin, Plate X, fig. 6) can scarcely represent a 

 Nummulite, and, indeed, he himself compares it with Nummulina 

 lenticitla, presumably of Defrance, which is now known to be an 

 Amphistegina. D'Archiac is probably correct in referring the 

 species to the genus Cristellaria.^ 



In the year following the publication of the paper above mentioned 

 appeared a joint paper by Nyst and Galeotti "Sur quelques fossiles 

 du calcaire jurassique de Tehuacan, au Mexique.'^ " The authors de- 

 scribe a number of fossils from a locality in the " Cordillere d'Ana- 

 huac," some 12 leagues W. N. W. of Tehuacan, and from an eleva- 

 tion of some 4000-7000 feet above the sea. The region is one of gray 

 and brown limestones, and said to be exceedingly rich in organic re- 

 mains. Indeed, it is questioned whether there exists another region 



^ Description des Animaux Fossiles du Groupe Nummulitique de I'Inde, pp. 

 36 and 163. 



^ Bulletin de I'Academie Royale des Sciences de Bruxelles, VII, 1840, pp. 

 212-21. 



