in most latitudes where any life is possible, so it is very evident that plants and animals, as we now see them, could not have made their advent upon the earth universally or simultaneously. Every geological fact contradicts both suppositions. Besides, to allege either is to claim, first, that all parts of the earth became habitable, for some form of life, at the same time, which is scarcely possible; and, secondly, such an allegation would do away with the main question of distribution, render superfluous most means of movement, and make it sheer nonsense to talk about the time, methods, and character of the distribution of that which had from the beginning been fully distributed. It is much more probable that life made its first advent upon this globe in some favored locality, and not everywhere at once.
It would seem as axiomatic a proposition as can be made in natural science, that life would make its first appearance on that part of the earth, or on that part of any developing planet, which by climatic and and all other concurrent conditions was first prepared, if not to originate, at least to receive and maintain it. Nothing can be more certain than that it could not make its first appearance on that part, or on any of those parts, wanting these conditions.
By concurrent conditions of climate or temperature, wherever the phrase is used herein, I mean such currents of air and ocean, such evaporation and condensation of water, such disintegration of rock, such electrical and chemical changes, new combinations, phenomena, and movements as are influenced by or accompany changing climate or temperature, together with all the secondary and remote effects caused thereby. And in speaking of the first appearance of life it matters not, to my mind, whether it was a creation, a development, or a transplantation; whether it was a lichen on the rock or a monad in the sea; a single solitary primordial cell, or one molecule of plasmic matter anywhere. This inquiry is not for the causes, methods, character, or extent of first life; it is simply and only concerning its probable primus locus.
If we are so fortunate as to discover where life began on the earth, it will be safe enough to rest upon the assumption that much, if not all, of the present life on the globe is its legitimate result and outcome.
I.
Are there, then, any data, any accepted facts touching the condition of our globe antecedent to the advent of plants and animals which would enable us to compare and contrast its past with its present condition, and which under known laws would indicate what portion of the earth's surface first became, by temperature, climate, and other concurrent conditions, habitable for life? Can any reasonable, probable, and still existing cause be discovered occurring in the very center of such first habitable portion which would have dispersed all vegetal and animal life and sent it in equal distribution through all the seas
