10 On the Foraminifera of America and 
gions of Chili, and partly with those of the warm regions of 
the Equator, but also offer some distinct species. 
We have still to speak of the Foraminifera of the equato- 
rial regions, partly of those at Payta, in Peru, and partly of 
those at the mouth of the Guayaquil. There are nine species, 
of which four belong at the same time to the localities already 
enumerated, while the other five are peculiar to these places. 
It is proved by the comparison of species, that the two coasts 
of South America present, as regards the Foraminifera, two 
entirely distinct and yet contemporaneous faunas. If we 
compare the species of the south coasts of the Atlantic ocean 
with those of the Antilles, or with the equatorial fauna, which 
includes one hundred and eighteen species, we find that among 
the latter there are none of the species of the south coasts, 
and although both series are in the same ocean, yet they are 
totally distinct. This result may be applied directly to the 
geology of the Tertiary period, and proves, that at inconsider- 
able distances on the same continent, entirely different and 
yet contemporaneous Faunas may exist. Different basins, 
therefore, which contain different species, may thus belong to 
the same epoch. 
Having given this numerical comparison of the species, let 
us now glance at the distribution of genera in the two Faunas 
of South America. In the order Monostega, we find that the 
genus Oolina, so common and so rich in species in the Mal- 
vinas, is not represented by a single species on the coasts of 
the Pacific. The order Stichostega affords the same result on 
the east coast; for, the genera Dentalina and Marginulina oc- 
cur there, while we have no species in the Pacific. The more 
numerous members of the order Helicostega are more uni- 
formly distributed, but yet each sea has its particular genera. 
Robulina, Polystomella, Peneropolis, and Uvigerina, occur on 
the east coasts in the Malvinas and in Patagonia; Valvulina 
alone occurs only on the west coasts in Chili, Bolivia, and 
Peru; Nonionina, Rotalina, Globigerina, Truncatulina, Rosa- 
lina, and Bulimina, are common to both oceans. Of the Hn- 
tomostega, Asterigerina is met with only on the east coasts ; 
Cassidulina on both sides. The Enallostega have the genera 
Guttulina and Globulina in the Atlantic alone ; while Bolivina 
