944 CARLOS SAPPER 



found a number of fossils which could be used for determining 

 the age of these deposits. The gypsiferous layers have not been 

 seen to the north of the vicinity of Haltum. 



Certainly these southern deposits belong to a lower horizon 

 than the northern deposits which were studied by Professor 

 Angelo Heilprin. This noted geologist has distinguished the 

 following horizons : 



(^) Limestones, gray or white in color, which can well be 

 studied in the cave of Calcehtok, the entrance of which is 200 

 English feet above sea level. Fossils are rare and the following 

 only were found : Pecten ?iucleus, Pecten sp., Margmella (sp. cf. 

 labiata),Potamides, or Cerithides, Oliva, Venus cancellata. Mr. Heil- 

 prin says that the age of this limestone is Miocene or Pliocene, 

 and not Oligocene as has been held by Alexander Agassiz.' 



(^) Limestones, red or reddish in color, lying above semi- 

 crystalline marble or yellow limestones, very fine-grained, resem- 

 bling the lithographic limestone of Solenhofen. Breccias of 

 limestone occur at the foot of the hills. In the red limestone a 

 Helix was found between Ticuli and Santa Elena, at an altitude 

 of 300 feet above sea level, and another fossil which seemed to 

 be a Macroceramus, in the cave of Calcehtok. Both these fossils 

 are terrestrial, but it could not be said with certainty whether 

 all the limestone is of terrestrial origin. The above limestones 

 occur in the hilly parts of Yucatan. I notice that Mr. Heilprin 

 does not mention the flint masses which are found in the same 

 regions and which are used in the vicinity of Ticul for the manu- 

 facture of mill stones. 



(^) The Pliocene limestone which predominates in the low 

 regions of the north of Yucatan and which was examined by Mr. 

 Heilprin, especially in Merida, and between Merida and Cal- 

 kini, Merida and Ticul, Merida and Tunkas, and between Tek- 

 anto and Silam. 



Professor Heilprin has found in it the following fossils : 



Pecten nitcletis, Tekanto, Merida, between Merida and Ticul. 



Pecten n. sp., " 



' Three Cruises of the Blake, Vol. I, p. 69. 



