[Assembly 
Fig. 17. 
is a cut representing the present appearance of these bluffs. They are 
about 150 feet above the lake. 
Fossils of the Tertiary of C/mmpIain. 
The fossils at present known as belonging to this formation are few 
in number, and will appear as a meagre list when compared with the 
upper secondary of the Atlantic coast. Of the most common is the 
sanguinolaria, and saxicava, a species of modiola and mytilus, both un- 
described as fossils^ and a balanus; also a few bones, apparently fossil, 
belonging to undetermined species. Fragments of shells of other ge- 
nera than those named above, too imperfect for determination, were met 
with at several places. It is probable, therefore, that the list will be 
much increased by future research. All that has yet been discovered, 
belong to species still living in the ocean, so that, geologically speaking, 
the formation is comparatively recent. It seems to be admitted or es- 
tablished, that a formation is the more recent, in proportion as the orga- 
nic relics are similar to these now existing, and the more ancient, as the 
same bodies, or the greater proportion, differ from those inhabiting our 
present seas and continents. 
Character of the Springs issuing from the Tertiary beds. 
The water of this formation is not only hard, in the common accep- 
tation of the word, but is often highly charged with sulphate of magne- 
sia, and sulphate of lime. Efflorescences of these salts, form in dry 
weather on the banks of clay in the vicinity of Crown Point, and may 
be collected in a pure state. Some wells in Addison, in the same clay, 
are so highly charged with Epsom salts, that they cannot be used ex- 
