Any explanation for such a remarkable number of stones accumulated in one place was so hard to be found in early days that it was necessary to resort to the supernatural, and Strabo records the legend that it was Zeus who bombarded with these projectiles the Ligurian tribesmen who attacked the early Phoenician traders and colonisers of the mouth of the Rhone. [Illustration: CAP MARTIN, NEAR MENTONE.] The Garonne, the last of the four great rivers of France, is the least interesting. As already mentioned it is of foreign birth, its head-waters being in the Maladetta chain of peaks in a Spanish portion of the Pyrenees, and the river has traversed about 30 miles before it enters France through the _cluse_ of the Pont du Roi. One of the two torrents in which the river begins its life plunges into a cavity in the rock, known as the Trou du Taureau, and does not appear again for two and a half miles. The Rhone also had formerly a small subterranean experience in its upper course, but the roof of rock has been destroyed. The course of the river is roughly north-westward until it reaches the formidable plateau of Lannemezan, where it is turned sharply to the east, carrying with it the waters of the Neste, a considerable stream fed by the snows of Mont Perdu and its big neighbours. In this part of its course the scenery is exceedingly fine. Before the snows have melted off the mountains there are always the pale blue-grey peaks flecked with sunny patches, and slopes forming a magnificent background to dark wooded hills full of purples and ambers, and in spring the more subtle browns turning to yellow and the palest suspicion of green. Immense views are obtained from the Lannemezan plateau, the frontier mountain-range stretching away east and west in a most imposing perspective of white peaks.