222 NATURAL SCIENCE [October 



the Cretaceous period from South Africa, which then became 

 directly connected with the lands of the northern hemisphere. 

 These mammals passed directly from the Euro-Asiatic Continent by 

 a land-bridge into North America. Then the isthmus of Panama 

 was formed, and many of the later Tertiary mammals were able to 

 wander back to the land of their primeval ancestors in the direction 

 of Patagonia. 



The theory is a pretty one, and we only wish the facts support- 

 ing it were more convincing ; for some theory of this kind would 

 explain many mysteries in the distribution of animals. For our own 

 part, we cannot recognise the very antique and ancestral features 

 which Dr Ameghino perceives in his ' Pyrotherium- fauna ' from 

 Patagonia ; but we must await the promised memoir in which the 

 remarkable new mammals in question are to be fully described. 



The Geology of Patagonia 



The interest aroused in the age of the tertiary deposits of 

 Patagonia will be still further fostered by a forthcoming paper 

 by Mr J. B. Hatcher of Princeton University, who visited the 

 district in 1896. Mr Hatcher has already recorded a few notes 

 in the American Journal of Science for September. In south 

 latitude 51° 31/ he discovered, near Cape Fairweather, a series of 

 marine beds with a fairly abundant invertebrate fauna, overlying 

 the Santacruzian formation, which in that locality are well-de- 

 veloped and full of fossil mammals. These Fairweather beds, as 

 Mr Hatcher has named them, have been deposited upon an eroded 

 surface of the Santacruzian formation, and consist of some 30 to 40 

 feet (as at present observed). The lower part is fine-grained, 

 incoherent sandstone, the upper a coarse, loose, but in places an 

 extremely hard conglomerate, which passes insensibly into the 

 overlying Patagonian shingle formation, from which it can only be 

 distinguished by the fossils it contains. The marine invertebrata, 

 according to Prof. Pilsbury, point to a Pliocene age, but they do 

 not promise to be of much service in determining the vexed question 

 of the age of the Santacruzian beds. Mr Hatcher at present believes 

 that the Fairweather beds are the equivalent of those beds dis- 

 covered by Darwin in North -Eastern Tierra del Fuego, and pro- 

 visionally referred by him to the Santacruzian beds discovered by 

 Fitzroy at the mouth of the Gallegos river, and he has, in support 

 of his view, fragments of crabs' legs very similar to those which 

 occur in the bluffs of San Sebastian Bay. The general dip of the 

 strata also lends colour to his deductions. We shall await with 

 interest the more detailed report which Mr Hatcher promises. 



