ORTMANN : TERTIARY INVERTEBRATES. 273 



L & S Ostrca ingens. L Turritella ambulacrum. Geryon pennianus. 



L Cucullcea alta. Turritella breantiana. 



The prevalence of Leonense species is opposed to the low level to 

 which this locality belongs, especially when we come to compare it with 

 the upper horizon at the same locality. All 5 species are found at Santa 

 Cruz. 



Mount of Observation, upper horizon ; 25-150' above tides. 



/ * Terebratclla patagonica. * Venus meridionalis. S *Scalaria nigulosa. 



*Nucula rcticularis. *Mactra darwini. * Infundibulum corrugatum. 



S *Arca patagonica. Mactra garretti. J SipJionalia noacliina. 



L & S * Ostrea ingens. * Corbitla hatcheri. S Valuta ameghinoi. 



Modiola ameghinoi. *Martesia patagonica. * Cancellaria gracilis. 



* Cardita elegantoides. S Dcntalium octocostcllatum. * Cancellaria cf. medina. 



P * Cardita incequalis. Calliostoma observationis. Action semilavis. 



P * Cardium piiclchum. Turbonilla cuevensis. Balanus varians. 



Of these 24 species, 15 are found at Santa Cruz (those marked*). This 

 horizon would correspond to about the middle of the series at Santa Cruz; 

 nevertheless it contains 2 distinctly Juliense, and no less than 5 Suprapat- 

 agonian species, while Leonense species are hardly represented. 



On the other hand, 9 species are found here, which have not been 

 found at Santa Cruz. These, however, cannot be taken as representing 

 a "Suprapatagonian " fauna. 6 of them are either new species, or have 

 not been found elsewhere ; of the rest 2 are found at San Julian (see be- 

 low) at a much lower level (Siphonalia noachina and Balanus vartans), 

 and V. ameghinoi has been found at Lake Pueyrredon, 600' above base 

 of Tertiary. That this latter locality cannot be regarded as Suprapata- 

 gonian will be demonstrated below. 



According to stratigraphical evidence, we are to expect that this local- 

 ity should belong to the upper Juliense or Leonense division of the Pata- 

 gonian beds : instead of that, Suprapatagonian species prevail, while a few 

 Juliense are intermingled with them. Thus it is impossible to say, to 

 which of Ameghino's and v. Ihering's subdivisions the beds of this local- 

 ity are referable. 



All the foregoing localities resemble more or less in the state of pres- 

 ervation of the fossils and in the matrix the type-locality at Santa Cruz, 

 and, indeed, geographically, they are not far distant from it. The first 



