140 
CHAMPLAIN DIVISION. 
New-York system. This view appears to be supported by facts of another kind, and, if 
any thing, of greater importance than those which belong to physical changes of surface. 
The fossils, for instance, belonging to this subordinate division as it now stands, do not 
exist in the succeeding rocks. Even where the Medina sandstone succeeds the Gray sand¬ 
stone of Oneida county, the fossils are not carried up. In fact, the entire fauna of the 
Champlain rocks became extinct at the close of the period during which they were depo¬ 
sited. From these facts, then, this division must be regarded rather in the light of a 
system, as we have just observed ; inasmuch as it is made up of a series whose characters 
are peculiar, and which do not belong to the preceding or succeeding era. It is true that 
the fossils of the succeeding rocks do not differ widely from those of the Champlain divi¬ 
sion : many genera continue, though all do not; yet it is worthy of remark, that those 
which disappear are quite limited in their ranges both vertically and horizontally. The 
genera Orthis, Atrypa , Strophomena , are continued ; but the crustaceans, as the Isotelus, 
Menus , with some others, are not found after this period. 
§ 17 . Recapitulation and summary of facts relating to the champlain division. 
1. The Champlain division is conformable to the succeeding divisions ; but as its members 
are placed upon the outside, and form a belt, consisting of a series of rocks adjacent 
to the primary, they are more disturbed and broken than those of the succeeding 
divisions. 
2. The inferior rock of this division, the Potsdam sandstone, is in the greatest force upon 
the western borders of Lake Champlain and the northern boundary of the State, 
nearly encircling the primary nucleus of Northern New-York ; but in some places 
it is absent on the south side of this nucleus, as in the Mohawk valley. In this 
case, the next superior rock, the Calciferous sandstone, forms the base of the divi¬ 
sion, and reposes upon the primary. 
3. The division embraces lithologically all forms of rocky strata : Conglomerates, breccia, 
sandstones, limestones, calcareous and sandy shales, and slate. Sandstones gene¬ 
rally form the base (but there are two locations where it is a conglomerate), and 
the summit of the division : the former are red or brown ; the latter, gray. The 
limestones occupy the inferior and middle portions of the series, and may be justly 
described under one name in a general system. 
4. The principal depositories of metallic bodies are at the base of the system, where the 
peroxide of iron has been forced upward from the primary, and hence occasionally 
occupies some of the inferior layers of the Potsdam sandstone. Galena and sulphu- 
ret of iron form veins in the limestone, but they are not important. 
5. Agriculturally the most important masses are the limestones or calcareous shales, all of 
which decompose and form a rich and valuable soil. Water and frost greatly faci¬ 
litate the process ; and masses of these shales, when thrown into heaps, speedily 
break and crumble into a dark argillaceous earth. 
