You would have thought, perhaps, that the side where the rough, hard rock was hidden by the fruitful vine, was the only part of the quarry worth looking at; but the other side, where the quarrymen were at work, was very interesting to anyone who would take the trouble to notice how the rocks lay, piled one upon another, and especially to one who had learnt a little about the different kinds of rock of which the earth-crust has been made. Even if you have never learnt much of what is called geology, by keeping your eyes open and your mind awake you may see a great deal in the stones which have perhaps seemed to you most uninteresting. A block of granite from one of the Dartmoor hills, and a piece of slate from a Welsh quarry--how different these two kinds of stone are! We see this at once; but they become much more interesting when we know that each has its own history. The granite is one of the fire-made rocks, so called because there are marks upon it, like letters written long ago, quite plain to those who have the skill to read them; which show that though it is now so hard, it was once soft, as soft as iron becomes when melted by very great heat. The mountains of Devon and Cornwall, the Grampians of Scotland, even Mont Blanc, the "Monarch of Mountains," are made of the grey or red granite which takes such a beautiful polish when cut that it is much prized for buildings. The piece of slate has quite a different history. It is one of the water-made rocks, in which so many fossils have been found; while in the fire-rocks there are no remains of anything which ever lived. The water-rocks are so called because water has had so much to do with the making of them; for they have been very slowly formed by the gravel and grains of sand which have been washed down by streams and torrents, and left behind in their course. In these slate and sandstone rocks the wonderful fossil animals, which are to be seen in the Museum, have been found. A fossil means what has been dug out of the earth; and numbers of animals are to be found buried deep in the rocks along the coast of Yorkshire--huge creatures which lived on the earth long, long ago, of which the hard parts, such as bones and teeth, have gradually been turned into stone. All this is very wonderful to think of, and I am sure the poet, who spoke of finding "sermons in stones," was wiser than he knew; but what will you say when I tell you that one kind of rock--the chalk with which you are so fond of drawing upon the black-board--is made of shells, most of them very tiny ones, which can be seen only by a microscope? What myriads of living things once made their homes in those little shells, and what sort of life they lived, we cannot tell; but there the shells remain in the white chalk, and the microscope will show them to you, as it shows so many hidden wonders in this wonderful world, where the very great and the very small meet on every hand.