TERTIARY SYSTEM. 
203 
not been examined very carefully, it is not at all improbable but that all may yet be found 
in the range of latitude which these fossils themselves now occupy. We have reason to 
-expect this. 
Upon Lake Champlain, Port Kent is the best point for procuring these fossils. The 
locality is about eighty rods south of the steamboat landing, in the clay bank, twenty-five 
feet above the level of the lake. If the shells are immersed in a weak solution of glue, 
the colors will revive and become permanent. 
For additional facts respecting this formation, see the Report of the Second district, in 
which the fossils are figured. 
The Tertiary system, as already stated, extends into -the valley of the Hudson. The 
fact of its extension is sustained by its continuity with that in the valley or basin of the 
Champlain. The character of the formation, in its southern prolongation, does not differ 
essentially from that already given. It may be regarded as extending to New-York bay, 
and probably westward into the valley of the Mohawk. Its full extent, however, can not 
be clearly defined. Its composition is quite uniform, as will appear by the analysis of the 
clay obtained at distant points. At Albany, this clay is an important material for making 
brick. In the process of extending the bounds of the city, a mass from ten to twenty feet 
thick has been removed, in order to bring the surface to a uniform grade. The banks 
exposed by this operation often present many curious contortions, of an anomalous cha¬ 
racter, and difficult to explain. A mass of ten feet thickness which has been exposed by 
a vertical section, is highly contorted, while its base rests upon horizontal strata. An 
illustration of this curious contortion is furnished in the following cut (fig. 33) . A portion 
Fig. 33 . 
on the left, which is bent, rests on the undisturbed clay bed below : in the middle it is still 
more contorted, and is a miniature representation of phenomena which are often witnessed 
in slates and shales of the different formations, and usually explained by the action of some 
uplifting force, accompanied by lateral pressure. This explanation is properly given in 
many instances. These contortions of the clay beds, however, seem to indicate the possi¬ 
bility of their production by other causes; for there will be found but few persons, who, 
after examining the instances here specified, will advocate the doctrine that these clay 
beds have been forced upward or wrinkled by lateral pressure, in the mode this force is 
usually supposed to act. It appears, after a careful examination of the circumstaces at¬ 
tending these irregularities, that they take place at points where the adjacent beds have 
been removed : they are then left unsupported on one side; and in consequence of this 
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