One thing more should be stated in connection with this theory, and that is that very long periods of time are demanded for the slow work of variation preserved by natural selection to accomplish the wonders attributed to it. To measure the time claimed by evolutionists by the lapse of years is simply out of the question; they ask for a long series of ages, each of which, though doubtless unequal, consists of millions of years. As the Rev. George B. Cheever remarks: "The first postulate of this philosophy is that of countless millions of years to work in, with no Creator, and with no authority that can bring it to book." To prove that such long periods of time have elapsed, during which organic forms have existed on the earth, the evolutionist triumphantly points to the revelations of geology, and there gives proof which there is, perhaps, no denying, of the lapse of time he pleads for; and also proof of organic forms of life in those various ages, fossilized remains of which are found in the strata of the earth's crust. If you say to the advocate of evolution that it is incredible that variations preserved by natural selection could result in the production of such a wonderful organ as the eye; he replies "that if numerous gradations from a simple and imperfect eye to one complex and perfect can be shown to exist, each grade being useful to its possessor, as is certainly the case; if further, the eye varies and the variations be inherited, as is likewise certainly the case; and if such variations should be useful to any animal under changing conditions of life; then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, should not be considered as subversive of the theory."[B] But with this statement and some further observations upon it, Mr. Darwin himself seems not altogether satisfied that he has removed the difficulty which he admits is enough to stagger anyone; "I have felt the difficulty," he says, "far too keenly to be surprised at others hesitating to extend the principle of natural selection to so startling a length."[C] [Footnote B: Origin of Species p. 143, (American Edition, 1883.)] [Footnote C: Ibid p. 146]