can do with our mines and railway tunnels is nothing in comparison with the work of Nature. In some of the great mountain chains—the Andes, the Himalayas, and the Alps, for instance—parts of the sides of mountains have fallen down, and rents many miles long have been left, showing what had been buried there in the different kinds of soil; and where rivers have cut deep, narrow channels through the earth, like the Cañons of Colorado, these natural miners have turned out more of the parts of “the puzzle of life” than we can with all our labour. It will not be easy at first to understand all the wonders I have to show you, but, when we get further on, you will see them one by one, and there will be very little difficulty. You know now where these things are to be found: principally in the ground you walk upon, without knowing all there is beneath you. The creatures here are much more wonderful than any of the monsters of fairy tale or fable, because the works of God are greater than the imagination of men who have invented the stories of flying dragons and griffins, and trees which grew up into the skies; but I cannot help thinking that this imagination shows what men thought _might_ once have been, and we shall see that “truth is stranger than fiction.” Creatures really did live on this Earth of such strange shapes and great size that the imaginations of those who wrote the fairy tales did not exaggerate much; and, though we know that no flying serpents or immense birds like the Roc are living now, and that there is no beanstalk which grows up into the sky while we are asleep, we shall see that there were lizards as large as whales, and birds taller than elephants, and great sloths stronger than the rhinoceros or hippopotamus, and ferns as high as oak trees, and mosses as large as gooseberry bushes; and that perhaps these animals and plants grew much faster than they do now, and that their dead bodies form a very large part of the earth of our World. This is not imagination, and when you go to a museum you can see all these wonders for yourselves, just as they were taken out of the earth; but of course the bones only of the animals are there. The flesh has long since gone away, and some of the stalks and fronds (leaves) only of the ferns remain to show us how large they must have been when they were alive and growing.