The third argument is essentially a display of Mr. Belloc’s inability to understand the nature of the record of the rocks. I will assume that he knows what “strata” are, but it is clear that he does not understand that any uniform stratum indicates the maintenance of uniform conditions while it was deposited and an absence of selective stresses, and that when it gives place to another different stratum, that signifies a change in conditions, not only in the conditions of the place where the stratum is found, but in the supply of material. An estuary sinks and gives place to marine sands, or fresh water brings down river gravels which cover over an accumulation of shingle. Now if he will think what would happen to-day under such circumstances, he will realise that the fauna and flora of the stratum first considered will drift away and that another fauna and flora will come in with the new conditions. Fresh things will come to feed and wade and drown in the waters, and old types will no longer frequent them. The fossil remains of one stratum are very rarely directly successive to those below it or directly ancestral to those above it. A succession of forms is much more difficult and elusive to follow up, therefore, than Mr. Belloc imagines. And then if he will consider what happens to the rabbits and rats and mice on his Sussex estate, and how they die and what happens to their bodies, he may begin to realise just what proportion of the remains of these creatures is ever likely to find its way to fossilisation. Perhaps years pass without the bones of a single rabbit from the whole of England finding their way to a resting-place where they may become fossil. Nevertheless the rabbit is a very common animal. And then if Mr. Belloc will think of palæontologists, millions of years after this time, working at the strata that we are forming to-day, working at a gravel or sand-pit here or a chance exposure there, and prevented from any general excavation, and if he will ask himself what proportion of the rare few rabbits actually fossilised are likely to come to light, I think he will begin to realise for the first time in his life the tremendous “gappiness” of the geological record and how very childish and absurd is his demand for an unbroken series of forms. The geological record is not like an array of hundreds of volumes containing a complete history of the past. It is much more like a few score crumpled pages from such an array, the rest of the volumes having either never been printed, or having been destroyed or being inaccessible.