IV



If we figure to ourselves the geologic history of the earth under
the symbol of a year of three hundred and sixty-five days, each day
a million years, which is probably not far out of the way, then man,
the biped, the Homo sapiens, in relation to this immense past, is of
to-day, or of this very morning; while the origin of the first
vertebrates, the fishes, from which he has arisen, falls nearer the
middle of the great year. Or, dividing this geologic year into four
divisions or seasons, primary, secondary, tertiary, and quaternary,
the fishes fall in the primary, the reptiles in the secondary, the
mammals in the tertiary, and man in the early quaternary.

If the fluid earth hardened, and the seas were formed in the first
month of this year, then probably the first beginning of life
appeared in the second month, the invertebrate in the third or
fourth,--March or April,--the vertebrates in May or June, the
amphibians in July or August, the reptiles in August or September,
the mammals in October or November, and man in December,--separated
from the first beginnings of life by all those millions upon
millions of years.

If life is a ferment, as we are told it is, how long it took this
yeast to leaven the whole loaf! Man is evidently the end of the
series, he is the top of the biological tree. His specialization
upon physical lines seems to have ended far back in geologic time;
his future specialization and development is evidently to be upon