To all such difficulties the evolutionist replies by alleging the incompleteness of the geological record, and modern handbooks on palæontology devote many pages to the task of explaining why incompleteness of the fossil record is just what we should expect, especially in the case of terrestrial animals. The reasons which they assign are convincing, but this particular mode of solving the difficulty is a rather precarious one. Evolutionists should not forget that, in sacrificing the substantial completeness of the record to account for the absence of intermediate species, they are simultaneously destroying its value as a proof of the relative position of organic types in time. Yet this, as we have seen, is precisely the feature of greatest strategic value in the palæontological “evidence” for evolution. We must have absolute _certainty_ that the reputed “ancestor” was in existence prior to the appearance of the alleged “descendant,” or the peculiar force of the palæontological argument is lost. It would be preposterous for the progeny to be prior to, or even coëval with, the progenitor, and so we must be quite sure that what we call “posterity” is really posterior in time. Now the sole argument that palæontology can adduce for the posteriority of one organic type as compared with another is the negative evidence of its non-occurrence, or rather of its non-discovery, in an earlier geological formation. The lower strata do not, so far as is known, contain the type in question, and so it is concluded that this particular form had no earlier history. Such an inference, as is clear, is not only liable to be upset by later discoveries, but has the additional disadvantage of implicitly assuming the substantial completeness of the fossil record, whereas the absence of intermediate species is only explicable by means of the assumed incompleteness of the selfsame record. The evolutionist is thus placed in the dilemma of choosing between a substantially complete, and a substantially incomplete, record. Which of the alternatives, he elects, matters very little; but he must abide by the consequences of his decision, he cannot eat his cake and have it.