ORTMANN : TERTIARY INVERTEBRATES. 285 



Patagonian" "Juliense" and "Leonense" are consequently to be dropped, 

 and the whole series should retain the old name: Patagonian beds. 1 



The contention of Amcghino that there is an hiatus in time between 

 Patagonian and Suprapatagonian beds, is completely erroneous. (See 

 Hatcher, 1900 a, p. 100.) 



Nevertheless, differences in the fauna are recognizable in different 

 localities. This refers especially to the fauna of the typical beds at Santa 

 Cruz. Some of the most characteristic species (for instance Cucullcea 

 alta, Struthiolaria ornata, Siphonalia domeykoand] have been found no- 

 where else in Patagonia, while they are abundant at Santa Cruz (includ- 

 ing Mt. of Observation, Las Salinas, etc.). This fact, in my opinion, is 

 due to the different development of the fades. The region around the 

 mo.uth of the Santa Cruz River is distinguished from the rest by its facies. 

 (See Hatcher, iQOob, p. 264.) All other localities have a more or less 

 sandy facies, often changing into a shell breccia, and these deposits ap- 

 parently were laid down in very shallow water, close to the shore, at any 

 rate, in shallower water than the deposits at the mouth of the Santa Cruz 

 River. This would sufficiently explain the slight differences of the re- 

 spective faunas. 



Geographically, the sandy facies seems to extend over all the country 

 from the coast of San Julian to the Cordilleras, and southward to Punta 

 Arenas. The clay deposits with concretions have only a local develop- 

 ment, near the mouth of the Santa Cruz River. 



Ameghino's "Piso Juliense" represents the local fauna of San Julian; 

 his "Piso Leonense" that of the mouth of the Santa Cruz River. 



The Patagonian beds, as understood here, were deposited in many 

 localities (observed at : Salt Lake, Arroyo Gio, Lake Pueyrredon) on the 

 eroded surface of the barren sandstones of the Guaranitic beds (see 

 Hatcher, 1900 a, pp. 93 and 108 ; at Lake Pueyrredon there is a basaltic 

 layer between both). In other places they overly other Tertiary beds, 

 but there are only two localities where this has been observed : Mayer 

 Basin, where the Upper Lignites are below them, and especially Punta 

 Arenas, where the Magellanian series precedes them in time, consist- 



1 The question remains whether we ought to call these beds by that name at all. The older 

 writers, especially d'Orbigny, understood under "Patagonian beds" deposits of a different age, 

 and the fact is, that most of d'Orbigny's Patagonian fossils do not belong to what is now called 

 by that name ; they come chiefly from Entrerios and the region of the Rio Negro. 



