ORTMANN : TERTIARY INVERTEBRATES. 321 



which comprises what is now Chili, Argentina, and southern Brazil, and 

 which he calls " Archiplata," and a northern part comprising chiefly 

 northern Brazil and Guiana, which he calls "Archibrazil," resp. "Archi- 

 guyana," or " Archiamazonas." This latter part was connected in Meso- 

 zoic times with West Africa by way of St. Helena, and he calls this 

 continental mass "Archhelenis." 



Archiamazonas or Archhelenis were separated completely from Archi- 

 plata by a broad stretch of sea, which extended across the present conti- 

 nent, where is now the valley of the Amazon River, the Cordilleras not 

 being yet formed, and thus a broad communication existed between what 

 is now the Atlantic and Pacific Oceans. 1 



Since Archiamazonas was connected with Africa, and this in turn in a 

 certain degree with India and Europe, the assumption of this old conti- 

 nent Archhelenis (which, by the way, differs only in the supposed geo- 

 graphical position from the "Atlantis" of previous writers) explains sat- 

 isfactorily the relations of the marine faunas of the West Indies (and 

 southern North America) with Europe. The connection of Archiplata 

 with Antarctica explains its relations to Australia and New Zealand, and 

 the existence of a broad connection of the Atlantic and the Pacific sepa- 

 rating Archiplata and Archhelenis (or Archiamazonas) explains the dis- 

 similarity of the southern and northern faunas of South America. 



Nevertheless, as we have seen, there are some remote affinities between 

 Patagonia and the West Indies, and even Europe, and apparently this is 

 due to the fact that confining our view to marine animals communica- 

 tion was possible in a certain degree between the shores of Archiplata 

 and Archiamazonas. This fact is most plainly seen in the presence of 

 Navidad fossils in corresponding deposits of northern Peru : the Navidad 

 beds were apparently deposited near the northwestern extremity of Archi- 



1 A former connection of the Atlantic and Pacific oceans up to Miocene times has been gener- 

 ally accepted, but this connection was placed chiefly, where is now the Isthmus of Panama. Ac- 

 cording to Hill, however (The Geological History of the Isthmus of Panama, etc. in : Bull. Mus. 

 Comp. Zool. Harvard Coll., vol. 28, 1898), a Central American barrier separating both oceans 

 has existed since Jurassic times, which was only temporarily interrupted at the close of the 

 Eocene. On the other hand, Hill admits that there must have been a broad and important con- 

 nection of oceans somewhere, but not at Panama. 



It seems to me that this broad connection is to be found in the sea across South America 

 mentioned above, and, personally, I am much in favor of the theory that the communication of 

 the Atlantic and Pacific took place, not at Panama, but farther south in the sea separating v. 

 Ihering's Archhelensis and Archiplata (see : Science, December 14, 1900, p. 929). 



