Farther down its course the great river's swift-flowing flood has on its banks the towns of Vienne, Valence, Avignon, Tarascon, and Arles, all by a curious chance on the left bank, although at Avignon and Tarascon there are sister towns on the opposite side, and Arles has a suburb across the water. Vienne and Arles still boast notable Roman structures, and Orange and Nimes, as well as the Gard, the last tributary the river receives before entering the period of its dotage in the Carmargue, preserve vast Roman buildings at no great distance from the Rhone. It is just possible that the great part this river has played in the making of France might have received a far less adequate recognition had these visual tokens of the days of imperial Rome vanished as did so many others. In its journey southwards from Lyons the character of the country traversed by the Rhone undergoes remarkable changes, and after Valence there is a decidedly southern aspect in the landscapes. The olive begins to appear, the vine is cultivated on all sides, and dark lines of cypresses become conspicuous. From Avignon the dusty limestone country extends across Provence to the sea, and the arid sun-baked hills terraced here and there for vineyards, the lines of sentinel cypresses, and the constant presence of the olive are the chief features of scenery that might be in Turkey, in Asia, or the Holy Land. And yet this river began life in an Alpine glacier and passed its middle age in the fertile lands of west-central France. The delta of the Rhone is a huge triangular area enclosed between the Grand Rhone and the smaller branch it throws off near Arles. It is called the Carmargue, and is a flat waste only cultivated at the river sides, and in certain patches helped by irrigation. Almost treeless in great portions, and exposed to the fierce mistral that blows its cold Alpine breath upon the delta whenever the mood arises, it is surprising to find any towns or villages in the whole district. Yet Aigues Mortes and St. Gilles, and a few villages, keep alive under the most adverse conditions. Below Arles, to the east of the river, and extending to the Etang de Berre, is the stony plain of La Crau, and there too, in spite of the climatic discomforts and lack of soil, two or three villages have come into existence along the main road between Arles and Aix-en-Provence. The Crau is probably more the work of the Durance than of the Rhone, which has deposited its burden of ice-carried boulders in the Lake of Geneva for ages, while the Durance in its comparatively short course from the Maritime Alps has no filtering vat, and in its periods of flood has forced millions of large stones down to the Rhone delta, gradually building up a barrier between itself and the sea, and necessitating a junction with the Rhone just below Avignon. When the sun beats down on the level waste of stones, whose depth averages from 30 to 45 feet, such heat is produced that a mirage is a not uncommon result.