188 The N.Z. Journal of Science and Technology. [May 
Upper Cretaceous beds, now generally regarded as Senonian; and in each 
.there are widespread Tertiary formations, with faunas of a southern type 
jtliat make correlations with European rocks a matter of difficulty. The 
Patagonian of South America and the Oamaruian of New Zealand are now 
generally regarded as Miocene, but both were originally thought to be 
older — -viz., Oligocene or Eocene—and to follow directly upon the Cre¬ 
taceous. In each country there was a school of geologists which contended 
for a clearly defined and important break between the two formations, and 
another which supported the view of a gradual transition. In each, again, 
quite recently there have been recognized faunas intermediate between the 
two in question, and diastrophic considerations have assumed an important 
place in elucidating the problems at issue. The paper under review, there¬ 
fore, possesses an exceptional interest for New Zealand geology. 
The author gives an excellent summary of previous views on the relations 
of the Cretaceous and Tertiary in Chile, and more particularly in Patagonia, 
.and considers it quite definitely established in both districts that the Cre¬ 
taceous and Tertiary are separated by a stratigraphical as well as a faunistic 
break. The hiatus between the two corresponds to the first phase of the 
Andine orogenetic movement (unlike New Zealand, where the first phases 
-of the Kaikoura orogenetic movements are not recognizable until near the 
close of the Oamaruian). These early Andine movements in the epirogenetic 
sense caused the breaking-down of the Brazilo-Ethiopian Continent, the 
formation of the South Atlantic basin, and the posthumous reopening of 
the graben-like depression between the Patagonian continental platform 
and the structural elements of central and northern Argentina. The first 
.of the Tertiary transgressions spreading from the South Atlantic over 
Patagonia is represented by the San Jorge formation, which is, like the 
•succeeding Patagonian formation, limited to Patagonia. It was not until 
the time of the Parana formation (Pliocene) that the ancient mass in the 
floor of the sierras of Buenos Ayres to the north broke down, admitting 
the Parana sea far to the north in the region of the Parana and Paraguay 
Rivers. 
The San Jorge formation, with which the paper mainly deals, was 
originally considered by writers of both schools as Upper Cretaceous in 
age, but the author concludes that it is Upper Palaeocene or Lower Eocene. 
In the palaeontological sense its fauna is of Tertiary character, being the 
forerunner of the Patagonian fauna, and containing a large number of 
genera unknown from the Cretaceous. Nevertheless, its fossils exhibit a 
number of similarities to the Pelecypoda and Gastropoda of the Upper 
Senonian of south Patagonia. This is regarded, however, as a natural 
result, since all three faunas sprang from the same South Atlantic - Antarctic 
centre, representing a continuous evolution of the original stock. We have 
almost exactly similar relations between the Piripauan, Kaitangatan, and 
Oamaruian faunas in New Zealand. 
Above the marine deposits of the San Jorge can be observed a peneplain 
of regional character. Upon this surface have been laid down the sediments 
with the earliest Patagonian mammal fauna ( Notostylops , Astraponotus , and 
Pyrotherium beds), the age of which is placed as Oligocene. The association 
of dinosaurs and mammals in Patagonia can be interpreted only by assuming 
that some branches of dinosaurs still persisted in the Tertiary. 
The succeeding Patagonian beds are accepted as Miocene; and the 
intimate relationship of their marine invertebrate fauna to those of New 
Zealand and Australia, as pointed out by Ortmann, is insisted upon, being 
explained by the persistence of a land-mass connecting South America 
and South Africa with its southern coast about the 38th parallel. This 
land-mass broke' up about the beginning of the Pliocene, for the succeeding 
