Strata laid down by water are in the first place in a horizontal position. Some subsequent force may have disturbed them, so that we may now find them standing up on edge like books in a library. But all human experience goes to show that they were not deposited in this position. Some disturbing cause must have taken hold of them since they were laid down, for the water in which they were made must have spread them out smooth and horizontal, each subsequent layer or stratum fitting "like a glove" on the preceding. Thus when we find two successive layers agreeing with one another in their planes of bedding, with every indication that the lower one was not disturbed in any way before the upper one was spread out upon it, the two are said to be =conformable=. But if the lower bed has evidently been upturned or disturbed before the other was laid down, or if its surface has even been partly eroded or washed away by the water, the strata are said to be =unconformable=, or they show =unconformability= in bedding. Of course, in all this we are dealing only with =relative= time. When we find one bed or stratum lying above another in their natural position, the lower one is of course the older of the two; but whether laid down ten minutes earlier, or ten million years earlier, how are we to determine? Ignoring the matter of the fossils they contain, must we not own that, though there is no way of telling just how much longer the lower one was deposited before the next succeeding, yet if the two are conformable to one another, and the bottom one shows no evidence of disturbance or erosion before the other was fitted upon it, the strong presumption would seem to be that no great length of time could have elapsed between the laying down of the two layers. To say that we have here a geological example similar to that of a modern American having been personally acquainted with Julius Caesar, would seem to be quite "inexplicable," as Herbert Spencer used to say. But if the life succession theory be true, we have just such a conundrum in our Fact Number Two, which is that =any formation whatever may rest conformably upon any other "older" formation=. The lower may be Devonian, Silurian, or Cambrian, and the upper one Cretaceous or Tertiary, and thus according to the theory millions on millions of years must have elapsed after the first, and before the following bed was laid down, but the conformability is perfect, and the beds have all the appearance of having followed in quick succession. Sometimes, too, though less frequently, these age-separated formations are lithologically the same, and can only be separated by their fossils!