ies added to the infinitude of
already recorded species. Our classifications will come to be, as far as
they can be so made, genealogies; and will then truly give what may be
called the plan of creation. The rules for classifying will no doubt
become simpler when we have a definite object in view. We possess no
pedigrees or armorial bearings; and we have to discover and trace
the many diverging lines of descent in our natural genealogies, by
characters of any kind which have long been inherited. Rudimentary
organs will speak infallibly with respect to the nature of long-lost
structures. Species and groups of species, which are called aberrant,
and which may fancifully be called living fossils, will aid us in
forming a picture of the ancient forms of life. Embryology will reveal
to us the structure, in some degree obscured, of the prototypes of each
great class.

When we can feel assured that all the individuals of the same species,
and all the closely allied species of most genera, have within a not
very remote period descended from one parent, and have migrated
from some one birthplace; and when we better know the many means
of migration, then, by the light which geology now throws, and will
continue to throw, on former changes of climate and of the level of the
land, we shall surely be enabled to trace in an admirable manner
the former migrations of the inhabitants of the whole world. Even at
present, by comparing the differences of the inhabitants of the sea
on the opposite sides of a continent, and the nature of the various
inhabitants of that continent in relation to their apparent means of
immigration, some light can be thrown on ancient geography.

The noble science of Geology loses glory from the extreme imperfection
of the record. The crust of the earth with its embedded remains must not
be looked at as a well-filled museum, but as a poor collection made
at hazard and at rare intervals. The accumulation of each great
fossiliferous formation will be recognised as having depended on an
unusual concurrence of circumstances, and the blank intervals between
the successive stages as having been of vast duration. But we shall be
able to gauge with some security the duration of these intervals by a
comparison of the preceding and succeeding organic forms. We must be
cautious in attempting to correlate as strictly contemporaneous
two formations, which include few identical species, by the general
succession of their f