502 Evolution and Distribution of Fishes 



it united with N. Zealand, Australia and New Caledonia. 

 Thus many western migrants spread eastward along fresh- 

 water routes, coincidentally with or earlier than. Marsupials 

 as well as many other animals and land plants, remnants of 

 which now occur on widely apart islands of southern seas. 

 This connection seems gradually to have broken up during 

 Miocene-Pliocene time. 



Eleventh: Extensive intercontinental changes took place 

 between Oligocene and late Miocene times, by which the 

 N. and S. American eastern bridge became sundered, and 

 the western one at times attenuated, at times broken. The 

 Afro-Brazilian and the Europeo-N. American bridges were 

 widely broken up and destroyed; the Archandean continent 

 was split lengthwise by a great fault and on the Pacific side 

 thrown down; but owing to Andean mountain elevation pro- 

 ceeding, it became closely joined with the Archenchelis or 

 Guiano-Brazilian mass. 



In stating such conclusions the writer desires it to be 

 understood that he expresses them not dogmatically, but 

 tentatively and suggestively. He states them the more 

 confidently from knowledge that they are more or less in 

 line with views already reached by de Lapparent, Neumayr, 

 Freeh, Arldt and others. They also undoubtedly furnish 

 a helpful key to many problems in the past distribution 

 of plants and animals that have engaged the writer's atten- 

 tion during the past forty years, and regarding which he 

 hopes yet to publish details. As in all scientific proenviron- 

 ments, whatever of the above can stand the test of continued 

 investigation will remain, whatever fails in this respect 

 should rightly be forgot. 



