Whatever then may be the real significance of the "days"--a point which the knowledge at present in our possession seems insufficient to explain--it seems very clear that something very different from natural days is intended. And this is a sufficient answer to the objection which is founded on that interpretation. That there would be very many points which as yet we are unable fully to understand, has been already shown to be not only possible but probable; and among them it appears this question of the true meaning of the days must be left for the present. When we come to consider subsequently the great number of points in which harmony between the narrative and discovered facts is brought out on investigation, [Footnote: Chap. v.] we may well be content to leave many points unexplained till our knowledge is greatly increased. SECTION 2. FIRST TRACES OF LIFE. The second objection has reference to the relative antiquity of the various forms of life, of which we find traces in the successive strata of the rocks. If it be assumed that the apparent coincidences which have been pointed out between the Mosaic narrative and the geological records are real, and that the traditional interpretation is the true one, then we ought to find-- 1. No traces at all of animal life below the Trias. 2. No traces of mammalia below the Cretaceous formation. But the examination of the rocks leads to a very different result. Traces of life have been found, probably in the Laurentian, certainly in the Cambrian rocks. The earliest known fish is the Pteraspis, which has been discovered in the upper Silurian formation at Leintwardine, in Shropshire. The first member of the reptilian order, Archegesaurus, occurs in the coal measures; and the first traces of a mammalian--two teeth--occur at the junction of the Lias and Trias. In every case, then, we meet with traces of life at a period long anterior to that at which we should naturally expect them. In order to ascertain the real weight of this objection we hare to investigate two points:-- 1. What are the animals to which the Mosaic Record refers? 2. What does it really tell us about the creation of those animals?