Thus we see that the Lake District is mainly composed of two different kinds of rocks, one of a clayey and easily-moulded nature, the other of an unyielding volcanic type, jagged and angular. It is very greatly due to the juxtaposition of these two different types that the Lake District possesses such diversity of outline. So much for the rocks of which the mountains are formed. But how came they to assume their present shapes? The answer is fairly simple. The Lake District, as we know it to-day, was quite recently, that is in a geological sense (a little matter of ninety-three million years ago!) a vast dome-like tract situated about four-thousand feet above the level of the surrounding country. After it had finally emerged from the sea, rain in torrents fell upon this dome. Rivers were formed. These followed the usual downward course of water, and as they flowed they slowly wore definite channels for themselves. Down these channels they swept, carrying with them small pebbles and earth which wore away the softer rocks underneath. This went on for millions upon millions of years. Hundreds of streams flowing in various directions, eating the rock out and bearing it in minute particles to the sea, left the higher grounds untouched and it is these higher grounds which we now know as the mountains of Lakeland. And now as regards the Lakes themselves. Influences into [Illustration: The Old Mill, Ambleside] which it would be tedious to enquire led to the warm winds and waters of the Gulf Stream being cut off from the district. The atmosphere became intensely cold. Instead of warm rain as heretofore, snow fell. This heaped up thicker and thicker until it compressed into ice which, in the form of glaciers, began to slide down the valleys previously hollowed out by the streams. The great Glacial Period set in. The glaciers tore up stones, earth and rocks and carried them along in their course. These great file-like masses of rock-embedded ice scooped out huge hollows in the river beds beneath. Then the Gulf Stream again brought its benignant influence to bear upon the district. Warmth came and rain fell again. The glaciers began slowly to melt and disappear: the rivers resumed their normal flow. At once the great hollows were filled with water and it was these water-filled hollows which first constituted our lakes. Since that time the lakes have in many cases been altered in shape. For instance, Derwentwater and Bassenthwaite were in times past one lake, but the _débris_ brought down and deposited by the river Greta has divided it into the two beautiful sheets of water with which we are now familiar. Incidentally, the glaciers had a great influence upon the shape and contours of our mountains, rounding, polishing and smoothing them into their present forms. Such is a very incomplete _resumé_ of the happenings of by-gone æons which have given to us our lovely district.