It is not easy, in the absence of documents, to attempt to give for Patagonia as a whole a detailed description of the pastoral industry, and to follow step by step on the spot its efforts to adjust itself to the natural conditions. But the analysis may be attempted in regard to the region between San Antonio and Lake Nahuel Huapi south of the Rio Negro,[71] the valley of the Rio Negro, and the tableland which stretches westward between the Neuquen and the Limay. This part of Patagonia is now easily accessible, and it is entered by two parallel railways. One starts from San Antonio on the Atlantic, and goes westward to Lake Nahuel Huapi. It has (1914) reached Maquinchao, on the tableland, mid-way across the Andes. The other starts from Bahia Blanca. At Choele Choel it enters the valley of the Rio Negro, and ascends it as far as the confluence of the Neuquen. Then it goes 130 miles westward as far as Zapala, at the foot of the first sub-Andean chains. Each of these lines is ambitious to attract the trans-Andeans. At all events, they are in a hurry to reach the humid zone at the foot of the Andes, which could maintain a busier traffic than the desolate tableland. [71] This was the area studied by the Commission of which Bailey Willis was chairman. The railway from San Antonio, and the road which is a continuation of it west of Maquinchao, cover a distance of 320 miles from the Atlantic to the Andes, and cross five distinct regions. The first is the coastal plain, composed of horizontal marine Tertiary sedimentary rocks, both of sand and clay. The plain rises slowly toward the west, and it attains a height of 650 feet at a distance of seventy miles from the coast. This coastal platform divides, on the north-west, the enclosed hollow of the Bajo del Gualicho from the Gulf of San Antonio. Its surface is very even. The gravel on it has formed a sort of conglomerate, and in spite of appearances, this gravelly soil is not bad for vegetation. It quickly absorbs the rain-water, which thus escapes evaporation. The vegetation is comparatively rich. There are no springs, but the autumn rains sustain _manantiales_ in the marly surface, and these do not dry up until the spring. During the summer the plain is deserted, and there is no water. But the flocks return in the winter and remain there until spring. There is very little snow, as the temperature is moderate. In spite of the density of the pastoral population in winter, the pasturage is not injured. The grass grows plentifully amongst the thickets. This is because the flocks leave the district before the season when the grasses flower and reproduce, so the next generation is secured. Part of the flocks which winter on the coastal plain pass the summer in the south-west, on the high basaltic tablelands of Somuncura. However, the whole of the surface of the tableland cannot be used permanently, or during the entire summer. There is plenty of water in spring, when the snows have melted. In the