50 
In Africa the Nummulite limestone has been considered of the 
Eocene period, and forms part of the Egyptian Pyramids, and is so 
compact as to be cut into sphinxes and other idols. 
In North America, the greensand of Virginia contains fossils of this 
formation, the Venericardia planicosta, &c.* At Alabama, one of the 
Southern states, a creature of enormous size has been discovered 
upwards of 100 feet long, and was first described under the name of 
Basilosaurus ; but Professor Owen, with his excellent knowledge of 
Comparative Anatomy, demonstrated that the animal possessed no 
saurian character, but was unquestionably a mammal, referable to the 
Cetaceous order and probably allied to the Dugong, one of the herbi- 
vorous whales; he has proposed for it the name of Zeuglodon, in 
reference to the peculiar yoked form of its molar teeth, and has stated, 
from its colossal dimensions and the small size of the bones of the 
extremities, the dense structure of the ribs, and the extreme elonga- 
tion of the bodies of the caudal vertebree, that it was one of the most 
extraordinary of the mammalia which the revolutions of the globe 
have blotted out from the number of existing beings. Subsequent 
discoveries of more complete skeletons have confirmed the accuracy 
of the reference of the Zeuglodon to the Cetaceous order. 
In South America, according to M. D’Orbigny, the Eocene period 
* Mr. Lyell states that, “ Out of 125 species of Eocene shells which I collected in the South- 
ern states, or which were presented to me, I have only been able to identify seven with European 
species of the same epoch. These are, Trochus agglutinans, Solarium canalieulatum, Bonellia tere- 
bellata, Infundibulum trochiforme, Lithodomus dactylus, Cardita, or Venericardia planicosta, and 
Ostrea bellovacina. But there are a considerable number of representative species, and an equal 
number of forms peculiar to these older tertiary strata in America. The Ostrea Selleformis, 
which may be considered as representing the Ostrea flabellula of the Paris basin, appears to be 
one of the most characteristic and widely disseminated Eocene shells in Virginia, South Carolina 
and Georgia, for I found it at Shell Bluff and on the Santee river, and the James river in Vir- 
ginia.”’—Lyell’s Travels in North America, vol. 1. p. 178. 
+ See Silliman’s American Journal of Science, vol. xliv. p. 411; and Dr. Gibbes in Proceed- 
ings of the American Acad. of Sciences, June 1845. 
