August 9, 1895.] 



SCIENCE. 



159 



ish texts are placed iu parallel columns. 

 Dr. Ameghino shows that the Spanish trans- 

 lation is full of errors and frequently 

 directlj' contradicts the statements made in 

 the English text. Most of the criticisms 

 seem to be thoroughly justified. In con- 

 clusion Dr. Ameghino says: "It only re- 

 mains for Mr. Lydekker to recommence his 

 work with more deliberation and more 

 material. If he should decide to do this I 

 offer him my assistance without any refer- 

 ence to his previous oversight of my re- 

 searches. My collection of fossil mammals 

 of Argentina contains about 750 species, 

 represented by 50,000 specimens, which I 

 place at his disposal with all the accom- 

 panying catalogues and notes." 



It is very significant that the most strik- 

 ing studies in paleontologj^ at the present 

 time are among the Theromora, or mam- 

 malian-like reptiles which Professor Seely 

 is describing from South Africa, and among 

 this rich, true mammalian fauna of South 

 America. Both the South American and 

 South African continents terminate at x^res- 

 ent in restricted land areas, but both give 

 evidence of a highly varied and rich land 

 vertebrate fauna in Mesozoic and early Ter- 

 tiary times. These facts alone point to a 

 far greater former extension of these land 

 areas, and even to extensive connections of 

 the southern continents, similar to those 

 which existed in former times between 

 the northern continents. Dr. Ameghino 

 has referred a large number of the Pat- 

 agonian mammals to the Marsupialia, and 

 they certainly present many striking re- 

 semblances to the Australian marsupials, 

 but none which appear to us absolutely 

 demonstrative of m.arsupial descent. 



A STILL later bulletin irom Dr. Ameghino 

 contains a notice of the ' Pyrotherium Beds ' 

 which were discovered in 1888 in western 

 Patagonia, in the province of ISTeuquen. 

 The last expedition made by M. Carlos 



Ameghino was especially directed to de- 

 termining the geological and faunal char- 

 acters of this formation. From the geolog- 

 ical point of view the results obtained are of 

 the greatest importance. The Pyrotherium 

 beds are of lacustrine origin and lie in a 

 vast cretaceous basin which is full of re- 

 mains of Dinosauria. At several points 

 these beds are found to underlie the Pata- 

 gonian deposits, which are generally con- 

 sidered contemporaneous with our lower 

 Miocene. The region where the beds are 

 exposed is verj^ similar to that of the Rocky 

 Mountain lake basins, absolutely desert, 

 deeply eroded, and almost everjT^'here so 

 dry that it is necessary to transport the 

 water supply long distances by muleback. 

 The most abundant and characteristic 

 mammal of these beds is Pyrotherium. It 

 is referred by Dr. Ameghino to a sub-order 

 of ungulates which he considers as the di- 

 rect source of the Proboscidia : "If this 

 large mammal had been found in Europe 

 or Asia no one would have hesitated to re- 

 gard it as uniting the characteristics of the 

 Dinotherium and Mastodon. The struc- 

 ture of the lower teeth, of the mandible and 

 of the femur is purely proboscidian ; the 

 astragalus, however, is of a profoundly dif- 

 ferent type, and to a certain degree is com- 

 parable to that of the marsupials. ' ' He con- 

 siders that the Pyrotheria represent a group 

 of ungulates which have I'elations to the 

 marsupials, but none the less represent the 

 ancestors of the Proboscidia. It is impos- 

 sible to accept such a conclusion, and it 

 seems difficult to determine from Dr. Ame- 

 ghino's figures whether this large mammal 

 represents a gigantic marsupial I'clated to 

 the kangaroo or whether it is the long 

 sought placental ancestor of the Pro- 

 boscidia. It presents a single pair of lower 

 incisors, like those of the diprotodont mar- 

 supials, but also somewhat similar to those 

 of the oldest types of Mastodon, such as 31. 

 angustigenis. 



