The Gran Chaco may be taken as a rough denomination for the whole of the Republic lying north of the Pampa, excluding the Andine fringe. This is a land of luxuriant vegetation with a warm and moist climate and, as might be expected, the products vary greatly from those of the temperate plains. Rice and the sugar-cane, castor-oil, sesame, and the poppy are all cultivated, but this part of the country is as yet scantily populated and quite undeveloped; there are therefore few surplus products to export. It is a region of great beauty, and travellers praise the silent tropical nights, whose darkness is relieved by myriads of fireflies, the primeval forests, and the magnificent rivers. But it is mostly virgin land and in many parts is peopled by savage inhabitants who make travel dangerous. [Illustration: A LONELY SCENE, SIERRA DE LA VENTANA.] The real Argentina is the Pampa; it is that vast and fertile champaign which makes the great Republic what she is, and to which she owes all her wealth and prosperity. Erroneous as is the popular idea that Argentina is merely a land of grassy steppes and rich cornfields, this is due to the fact that all except specialists have confined their travels to the Pampa. It extends from Cordoba to the Rios Negro or Colorado. In it are contained the great and growing towns, and from it these towns draw their prosperity. It is a country to delight the heart of the agriculturist. In many countries of South America the traveller passes through interminable jungles sparingly scattered with patches of cultivation where a few bony cattle scour for a livelihood. In the Pampa there is rich tilth and fine pasture; magnificent red and white beasts graze and fatten, standing knee-deep in the fresh grass, and sheep innumerable are raised. The dead level of the land is not quite unbroken, for south of the Plate estuary there are two small mountain ranges, the Tandil and Ventana. They never exceed 2,800 feet. In the east the rainfall is generally satisfactory, but it becomes scanty in the western districts. The winter is cold, the summer decidedly hot, but the climate is not intemperate, and might be called pleasant but for the fierce hot and cold winds which disturb enjoyment and are in some cases prejudicial to health. This brief summary must, for the present, suffice for the four regions; as we survey the country more in detail, we shall have opportunities of describing their characteristics more fully. It remains, however, to take a brief survey of several features which can better be described while we look at the country as a whole. The geology of Argentina greatly interested Darwin. He says:[4] "The geology of Patagonia is interesting. Differently from Europe, where the Tertiary formations appear to have accumulated in bays, here along hundreds of miles of coast we have one great deposit, including many Tertiary shells, all apparently extinct. The most common shell is a massive, gigantic