measuring time by Falstaff's Shrewsbury clock, without violent sense of wrong, as one could do it on the Pacific Ocean; but the triumph of all was to look south along the Edge to the abode of one's earliest ancestor and nearest relative, the ganoid fish, whose name, according to Professor Huxley, was Pteraspis, a cousin of the sturgeon, and whose kingdom, according to Sir Roderick Murchison, was called Siluria. Life began and ended there. Behind that horizon lay only the Cambrian, without vertebrates or any other organism except a few shell-fish. On the further verge of the Cambrian rose the crystalline rocks from which every trace of organic existence had been erased. That here, on the Wenlock Edge of time, a young American, seeking only frivolous amusement, should find a legitimate parentage as modern as though just caught in the Severn below, astonished him as much as though he had found Darwin himself. In the scale of evolution, one vertebrate was as good as another. For anything he, or any one else, knew, nine hundred and ninety nine parts of evolution out of a thousand lay behind or below the Pteraspis. To an American in search of a father, it mattered nothing whether the father breathed through lungs, or walked on fins, or on feet. Evolution of mind was altogether another matter and belonged to another science, but whether one traced descent from the shark or the wolf was immaterial even in morals. This matter had been discussed for ages without scientific result. La Fontaine and other fabulists maintained that the wolf, even in morals, stood higher than man; and in view of the late civil war, Adams had doubts of his own on the facts of moral evolution:-- "Tout bien considere, je te soutiens en somme, Que scelerat pour scelerat, Il vaut mieux etre un loup qu'un homme." It might well be! At all events, it did not enter into the problem of Pteraspis, for it was quite certain that no complete proof of Natural Selection had occurred back to the time of Pteraspis, and that before Pteraspis was eternal void. No trace of any vertebrate had been found there; only starfish, shell-fish, polyps, or trilobites whose kindly descendants he had often bathed with, as a child on the shores of Quincy Bay.