"Here, then, we have a bird, which, in its whole structure, shows a close affinity to the smaller typical perching birds, but which has departed from all its allies in its habits and mode of life, and has secured for itself a place in Nature where it has few competitors and few enemies. We may well suppose,* [[*Note characteristic phrase "We may suppose that,--." G.]] that, at some remote period, a bird which was perhaps the common and more generalized ancestor of our thrushes, warblers, wrens, etc., had spread widely over the great northern continent, and had given rise to numerous varieties adapted to special conditions of life. Among these some took to feeding on the borders of clear streams, picking out such larvae and mollusks as they could reach in shallow water. When food becomes scarce they would attempt to pick them out of deeper and deeper water, and while doing this in cold weather many would become frozen and starved. But any which possessed denser and more hairy plumage than usual, which was able to keep out the water, would survive; and thus a race would be formed which would depend more and more on this kind of food. Then, following up the frozen streams into the mountains, they would be able to live there during the winter; and as such places afforded them much protection from enemies and ample shelter for their nests and young, further adaptations would occur, till the wonderful power of diving and flying under water was acquired by a true land-bird." (_"Darwinism,"_ p. 81-82.) Lines of Evidence. The evolutionary hypothesis (both in its atheistic and theistic or "Christian" form) is understood to rest on the following lines of proof: i. _Primary:_ The evidence of palaeontology (the study of fossil remains in the rocks). The surface of the earth underneath the top soil consists of layers of rock. Some of them are made up of lime deposits, others of the shells of shell-fish, others of sand-stone, others of dead trees of the forest (coal), all of them turned hard by the pressure of the weight lying on top of them. Besides these sedimentary rock there are formations like granite, showing the influence of heat. Digging among the sedimentary rock (limestone, sand-stone, principally) we come across preserved remains of all sorts of animals; some just like those which live to-day, some similar but somewhat different, others quite dissimilar from living animals of our day. These are the fossils. Now, evolutionists assert that the oldest and simplest animal and plant remains are found in the oldest layers of rock. This is said to prove that in the history of plants and animals on earth, the simplest forms are the oldest and that later the more complex forms were developed from these. LeConte states the matter thus: "The farther back in time we go, the simpler the forms of animal and plant life become, and these forms occur in the order of their origination, just as if they were developed one from another."