THE PHYSICAL EVOLUTION OF ACADIA. 
5 
where they come in contact with the Cambrian rocks, are always 
found to run beneath them. 
It is supposed that this system is of the same age as the 
Laurentian limestones of the Grenville area near Ottawa, though 
the latter show a greater metamorphism, and the whole set of 
strata there are greatly disturbed and injected with masses of 
intrusive rocks carrying various crystalline minerals. In the 
New Brunswick area, near the Bay of Fundy, these foundation 
rocks are brought up in several parallel ridges, arranged 
in echelon, and separated by the strata of the succeeding terrane. 
Were we to attempt to interpret the physical history of 
this region, as shown in the “ Upper Series” of the Laurentian 
area, it might be stated in general terms as follows: — 
First — Omitting the lower and more altered part, with its 
feldspathic schists and its marbles, there is 
Second — A quartzite formation (originally a fine sand) 
marking the prevalence of ocean-shoal conditions — a sea bottom 
traversed by strong marine currents, and showing few evidences 
of the existence of living beings other than worm burrows, and 
casts and exuviae of these animals. 
Third — A thin formation of silicious mud, formed in stiller 
and deeper water than the above quartzites, as the ocean bottom 
sank. It contains strap-like organisms, probably seaweeds. 
Fourth — A great limestone formation. In the lower part this 
is chiefly a carbonate of lime with disseminated carbonaceous 
matter; in the middle it becomes magnesian and in the upper 
part it has many intercalated beds of fine grained pyritous trap 
and of fine grained gray clay- slate. A formation like this exposes 
a natural succession of members of a great sedimentary series. 
It is in the limestone that we find remains of the primitive reef 
builder, Archceozoon, and it is such a formation as in later ages 
would indicate pure ocean waters and a warm temperature. 
Synopsis . — To sum up this history there was: — 
First — A rather deep ocean with muddy and some calcareous 
deposits. 
