ion, can we formulate a few of the general laws, or perhaps
I had better call them general conclusions, respecting life, in which
all palaeontologists may agree? Perhaps it is not possible to do this
at present satisfactorily, but the attempt may do no harm. We may,
then, I think, make the following affirmations:

"1. The existence of life and organization on the earth is not
eternal, nor even coeval with the beginning of the physical universe,
but may possibly date from Laurentian or immediately pre-Laurentian
times.

"2. The introduction of new species of animals and plants has been a
continuous process, not necessarily in the sense of derivation of one
species from another, but in the higher sense of the continued
operation of the cause or causes which introduced life at first. This,
as already stated, I take to be the true theological or Scriptural as
well as scientific idea of what we ordinarily and somewhat loosely
term creation.

"3. Though thus continuous, the process has not been uniform; but
periods of rapid production of species have alternated with others in
which many disappeared and few were introduced. This may have been an
effect of physical cycles reacting on the progress of life.

"4. Species, like individuals, have greater energy and vitality in
their younger stages, and rapidly assume all their varietal forms, and
extend themselves as widely as external circumstances will permit.
Like individuals also, they have their periods of old age and decay,
though the life of some species has been of enormous duration in
comparison with that of others; the difference appearing to be
connected with degrees of adaptation to different conditions of life.

"5. Many allied species, constituting groups of animals and plants,
have made their appearance at once in various parts of the earth, and
these groups have obeyed the same laws with the individual and the
species in culminating rapidly, and then slowly diminishing, though a
large group once introduced has rarely disappeared altogether.

"6. Groups of species, as genera and orders, do not usually begin with
their highest or lowest forms, but with intermediate and generalized
types, and they show a capacity for both elevation and degradation in
their subsequent history.

"7. The history of life presents a progress from the lower to the
higher, and from the simpler to the more complex, and from the more
generalized to the more specialized. In this progress