852 president's address. 



furnished me with a co})}' of his Treatise "Das neutropische Floren- 

 irebiet uud seine Geschichte," (Engler's Jahrbuch, 1893). This able 

 treatise deals with matters of special interest to us, and therefore 

 deserves notice in this place, but I find that I have not space to 

 refer to it at the length which it deserves, and I must therefore 

 now confine myself to stating his main arguments, at tlie same 

 time recommending those interested to study the original work. 

 The author sets himself to upset Wallace's axiom of the per- 

 manence of continents and oceans which would, if true, require 

 that South America was always cut ofi" from connection with 

 south-eastern Asia as it is at present, and he disputes the validity 

 of the assertion that the bottoms of oceans over 1000 fathoms in 

 depth could never have been dry land. He says that greater 

 depths onl}' indicate longer time for subsidence. The effect of 

 separation at different epochs would be that we should find the 

 fauna limited to the groups which had reached their development 

 before then, and he j)oints to the Pacific Islands, where the 

 tertiary fauna are absent altogether, as proof of their isolation 

 in jNIesozoic times, while on the other hand lizards, ancient types 

 of moUusks and insects are found. 



The author divides South America into three regions. The 

 northernmost has affinities with North America, the middle one 

 with Africa, ^Madagascar and Bengal. These regions he suggests 

 after an investigation of the fresh water fauna. They were in 

 the Cretaceous and early Tertiary separated b}^ ocean. He 

 concludes that a great continent which he calls " ArchUelenis " 

 extended across the Atlantic to Africa and beyond; this possessed 

 probably no mammalia, but a rich fresh water fauna and identical 

 reptiles and amphibia. The lower region he calls " Archiplata," 

 it was formerly connected with New Zealand, and partly 

 with Australia and Tasmania. The early Tertiary mammals 

 existed in this region, but not in Archhelenis. The Dasyure 

 group connects with Australia. The Anoplotheridce and Tliero- 

 domyidcE have affinities with the Eocene fauna of the old world. 

 Argentina can only have received her Eocene mammals across 

 antarctic lands. In the Pliocene North and South America 



