As our geological Hamlet speculated over these bones of extinct monsters, the ideas of Linné and Cuvier struggled fiercely in his mind with the new, heretical ideas inspired by Lyell. How was it that these ancient, extinct animal forms of America resembled in every detail and in the most marked characteristics certain living American animals? Before him were the relics of past sloths, armadilloes, and giant-llamas. In the actual America, also, there were sloths, armadilloes, and llamas, though with some difference. And nowhere else on earth, either in past or present time, were there sloths, armadilloes, and llamas. Cuvier had replied, God had pleased to create those ancient megatheria, glyptodons, and macrouchenias of America. Then, one day, he sent his destructive catastrophe, and swept them all away, as a sponge goes over the table. Then, in the empty land, he created afresh the sloths, armadilloes, and llamas of to-day. But why had God made the new animals so like the old that the modern zoologist has to class the megatherium in the same narrow group as the actual sloth, the ancient glyptodon with the modern armadillo, and so on? Darwin, who had studied theology, was unshaken with regard to God himself. However, something occurred that occurs so often and with such good result in the history of thought. It appeared to him that the notion of a direct creation is by no means the simplest way of explaining things, but the most puzzling and complicated. Darwin believed in Lyell. There had been no destructive catastrophe at all to sweep away the megatherium and its companions. They had disappeared gradually, by natural means. Was it not much more rational to suppose that the actual sloths and armadilloes came into being gradually, by natural means? Part of the old animal population had not perished, but been transformed into the actual species. There was a bond of relationship between the past and the present. One or other grotesque and perhaps helpless giant form may have completely disappeared in the course of time. But the golden thread of life was never entirely broken. Other and more fortunate species had preserved the type of the sloth, the armadillo, and the llama; they had developed naturally into the living animals of America. God might remain at the groundwork of things. He had launched matter into space, and impressed natural laws on it. But these sufficed for the further work. They created America. They developed the mammal into the sloth and the armadillo in the days of the megatherium and the glyptodon. They maintained these types in the country, in a straight line of development; the progressive principle of life bringing about the extinction of certain forms, and transforming others by a more fitting adaptation to their environment.