Baron Humboldt on Rock Fm^matlom. 
the beds beneath the chalk, M. Brongniart has even recentij 
proposed to designate the tertiary formations by the name of 
upper secondary deposites, {Sur le glsement des OphioUthes^ 
p. 37). Compare also the very interesting geognostical discussions 
contained in iff. de Bonnard "' b Traite des Roches^ p. 138, SIO, 
and 91%) 
The distinction of four deposites v/hich we have successively 
named, and of which three are posterior to the development of 
organic life upon the globe, appears to me worthy of being re- 
tained, notwithstanding the passage of some formations to others 
of a very different character, and notwithstanding the doubts 
which several very distinguished geognosts have founded upon 
these passages. The classification of deposites marks great 
epochs of nature ; for example, the first appearance of some pe- 
lagic animals (zoophytes, cephalopodous mollusca), and the si- 
multaneous destruction of an ^enormous mass of monocotyle- 
dons. It presents as it were points of rest to the mind, and by 
keeping in view that the formations themselves are much less 
important than the great divisions, we have often an opportu- 
nity, on advancing from high mountains toward the plains, of 
observing the varied influence which the association of primi- 
tive and transition rocks, and that of secondary and tertiary 
ones, have exercised upon the inequality and configuration of the 
ground. It is owing to this influence, that the aspect of the 
landscape, the form of mountains and platforms, and the cha- 
racter of the vegetation, vary less, when we travel parallel to the 
direction of the beds, than on cutting them at a right angle. 
(Greenough, Crit. Exam, of Geology, p. 38.) 
I continue, by following Messrs de Buch, Freiesleben, Bro- 
chant, Beudant, Buckland, Raumer {Geb, von Nieder-Schles., 
1819), and other celebrated geognosts, to group the indepen- 
dent formations according to the divisions, into primitive, transi- 
tion, secondary, and tertiary deposites, without troubling myself 
about the impropriety of the greater number of these denomi- 
nations. I continue to separate the clay (with lignites) super- 
imposed upon the chalk, from that which is beneath it, and the 
chalk itself from the more ancient secondary formations. But 
these distinctions, by beds and groups of beds, so useful in the 
description of a deposite of small extent, ought not to prevent 
