Remarks on American Rock Formations. 255 
mass, and our former ignorance of the true Poweins of the 
shells, have been the sources of our erroneous views. 
The second error of American geology, is the extending 
or covering of the western country, and the back and upper 
parts of New Yo rk, with secondary rocks. It was taken for 
sranted that all horizontal rocks are secondary, and as the 
rocks of these parts of the United States are horizontal in 
their position, so they were supposed to be secondary; and 
as such are copied by every writer I am acquainted a 
With those writers, who do not admit a transition or inter- 
mediate class, the generalization of inclination, and no in- 
cUnAsOn is admissible ; but is not so, when a transition class 
orms a part of the system. This class, (the transition,) is 
uplifting or downfalling force, or both, have existed ; but it 
is ne certain that either or both these forces have acted i in 
ized, as has been done by Mr. Maclure. 
Innumerable are the facts, which have fallen under my 
observation, which show the fallacy of adopting inelination 
for the character of a class, and the geological boundaries of 
the two classes in question, in the United States, abound in 
such facts. Those rocks are highly inclined, whose proto- 
types are horizontal towards the west, or otherwise removed 
from the mountain range. The analogy or identity of rocks 
I determine by their fossils in the first instance, and their 
position and mineralogical characters in the second or last 
instance. One observ: ation, and then shall terminate this 
ist as mountain or level es, those Pat which are S not 
nearer than the bituminous waa depositions resting upon 
them, are usually more or less inclined ; but if the primitive 
be far removed from such rocks, no rule can be given; they 
may be horizontal or inclined. Also, the greater the extent 
