496 Reviews. [ Oct., 
have produced the only known Enaliosaurian and Land-shells, and 
the first known Myriapod, of that ancient date. 
The Devonian period of Acadia was remarkable for its rich 
vegetation, and for its ancient air-breathing insects,—the oldest of 
all known land-animals; while to the igneous outbursts of this era 
Dr. Dawson refers the formation and upheaval of the metallic riches 
of the region. 
The Silurian rocks were spread out on the shores of the rocky 
lifeless continent which then stretched westward from Labrador ; 
the commencement of the period being characterized by muddy 
shallows and coral-reefs in the deeper sea; the termination of it 
witnessed the breaking up of this sea-bed, and the production of 
greater inequalities by extensive processes of upheaval and dis- 
turbance, accompanied by a gradual but entire change in the 
animal life of the region, leading up to that assemblage which 
characterized the Devonian epoch. 
At the base of all these deposits occur the great Laurentian and 
Huronian series,—the former deposited in an ocean of whose shores 
we are utterly ignorant, and the latter characterized by the dis- 
turbance of its quietude, the breaking up of its bed, the metamor- 
phosis of its sediments, and the ejection of vast showers of lava, 
ashes, and scoriz. 
Thus, in a few words, we have a sketchy outline of the Geology 
of Acadia; and we have only now to ask, What new lesson does 
this wondrous history teach us? Does it explain anything of 
which we were formerly ignorant, or does it expose the naked 
pinchbeck which we once mistook for the gold of truth ? 
Dr. Dawson thinks he can infer something comparatively new ; 
and he also tries to prove untrue something that is now compara- 
tively old; and both these efforts relate to a kindred subject, per- 
haps we should say to the same. In other words, he reproduces 
his idea of Geological Cycles, regarding each great geological period 
as forming a geological cycle in which the diversified conditions of 
land and water were, to a certain extent, successive ; and he strives 
to show that the theory of Homotaxis is utterly erroneous, and 
that, for instance, the Carboniferous formation is, as a whole, and to 
a great extent, division for division, the contemporaneous equivalent 
of the European Carboniferous system. 
We ought to mention, in conclusion, that the work is illustrated 
by an excellent engraved geological map, printed in colours; and 
by a large number of woodcut views, sections, and figures of fossils. 
