858 The American Naturakst. [October, 
In contrast to this small extension of marine Triassic and 
Jurassic rocks, the Cretaceous deposits cover a very large area in 
South America. Marine Cretaceous fossils are found in nearly 
all parts of the Cordillera from South Patagonia to East 
Venezuela, and Mr. White has discovered a rich fauna of the 
Cretaceous formation of East Brazil. The invasion of con- 
tinental areas by the sea at the earlier Cretaceous period, which 
has been observed. in many parts of Central Europe, seems to 
have taken place on a much larger scale in both Americas. We 
know now, by the investigations of Hill and White, that a part 
of the Cretaceous strata of Texas formerly regarded as Upper 
Cretaceous belongs to the lower part of this formation. The 
Cretaceous formation of Mexico appears as a direct continuation 
of the Texas deposits; and as far as our present knowledge 
extends, the relations between the faunas of the older Cretaceous 
of these regions and those of Venezuela, Colombia, and North 
Peru are very intimate. It is interesting to see certain char- 
acteristic fossils of the Lower Cretaceous of the north reappear in 
the south. The famous genus Aucella, widely distributed on the 
slopes of the North Pacific, has been recently mentioned by N. 
Ritin from Mexico; by White from Brazil; I know it also from 
the invirons of Lima associated with Ammonites of the Neocomian 
of Europe. The Cretaceous sea which covered the central part 
of America probably continued farther to the east. We find, there- 
fore, some remarkable relations between the Lower and Upper 
Cretaceous faunas of South America, especially of Colombia and 
Peru, and those of North and West Africa. Some forms of Buthi- 
ceras known from Algiers are found abundantly in the Upper 
Amazonian region. The truly marine deposits of the central part 
of America disappear to the north and the south, and seem to be 
replaced by sandy deposits without marine fossils. Probably a 
great part of the red sandstone formations which occur 
in Brazil, Venezuela, Bolivia, and in the north of the Argentine 
Republic, take the same place relative to the marine sediments of 
the older Cretaceous as do the Atlantosaurus beds, the Trinity 
and Tuscaloosa formations in the north,—namely, underlying 
themselves or forming an equivalent of them. 




