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 ‘ Pyrotheriwm-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 Jowrnal 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. 
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