22 
GEOLOGY OF THE SECOND DISTRICT. 
is propagated and conveyed down from one generation to another. The name remains, hut 
the error is either forgotten, or at least ceases to mislead.- The only duty, therefore, in rela¬ 
tion to those names which have been so long in use, is to restrict them to certain limits. 
This being done, we may subdivide those rocks into groups, or series, giving those names 
to the groups, or series, which shall be derived from that section of country where they 
are well developed ; our nomenclature may then be completed by giving local names to in¬ 
dividual rocks where it is necessary, observing to select those places at which they are all 
the best developed. In following this plan, we are in less danger of overrating the value of a 
name, or falling into error by mistaking a name for an idea, or an idea for a fact. 
I may here state that the upward limits of the Transition class may, with great propriety, 
be placed at the Old Red Sandstone, or Old Red system, or Devonian, as it is often termed; 
it embraces the rocks between the primary and the old red, a limit which can generally be 
defined with sufficient accuracy and precision. 
Adopting the names for the principal divisions of them as now proposed, I shall follow still 
farther those subdivisions of the primary which have also been long in use, and which have 
received the sanction of some of the most eminent geologists. Those subdivisions are as 
follows : Unstratijied, Stratified and Subordinate. The two first must ever remain as well 
marked divisions, which it will be useful to observe ; the term subordinate, applies very well 
to a class of rocks which appear irregularly among the greater masses, but which are always 
limited in extent; and they are not found occupying the same relative position, but repose 
sometimes upon the primary, and sometimes upon the transition, secondary, or even tertiary. 
Of the Primary Formations of the Northern Division of the State. 
The Primary formations occupy by far the largest part of the area between Lake Cham¬ 
plain and the St. Lawrence river. They constitute not only all of that portion which is the 
most elevated, as the mountains in the vicinity of the head waters of the Hudson, Ausable, 
Racket, Black and St. Regis rivers, but also large tracts of the less elevated portions in the 
immediate neighborhood of the great valleys, as the Champlain, Mohawk and St. Lawrence. 
As a whole, or as a class, they are well characterized ; and we find but few places where 
there are gradations of the Primary into the Transition in this District, few rocks which can, 
with propriety, be termed metamorphic ; they, however, present a great diversity of aspect 
and of character, and in this respect they form an interesting assemblage of rocks. 
I have just observed, that there are few transitions of the primary into the sedimentary 
rocks. There are, however, many transitions among the primary masses themselves ; and 
we often find intermediate ones, which are with difficulty placed under appropriate names. 
This is not, however, a matter of much consequence ; it is a result, or a fact, which we 
should expect, when we consider the origin of the primary rocks, and the agencies to which 
they have been exposed. In studying, or describing them, if is important to keep this fact in 
mind. 
