Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.2): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

98 MAR-CHiaUlTO RANGES OF HILLS. AugUSt heads, nothing like an opening could be detected, though the beach was scrutinized with good glasses, as well from the deck as by those who looked down upon it from aloft as we sailed by. I suspect that there has been some confusion of ideas respecting the little river San Pablo, and a supposed entrance to the lagoon : but, be this as it may, very great difficulty would be found in attempting to form a large and permanent communication at a spot so exposed to heavy south-east gales. At Port Valdez (in latitude 42° S.) the entrance is some- times completely blocked up by shingle and sand, during and after a strong south-east gale ; and I think it probable that such an effect would be caused here, at times, whether there were a natural or an artificial opening ; and as there is no great rise and fall of tide, I much doubt whether the opening would be again cleared, as at Port Valdez, by the mere ebb and flow of water. In the vicinity of Mar-chiquito, the country (campo) is very fertile, and well watered. Sheltered to the south by a range of down-like hills, whence numerous small brooks originate, it gives abundant pasturage to many thousands of cattle, and is considered by the Buenos Ayreans to be the finest district of their territory. This range of hiUs extends in a west north- west direction for more than fifty leagues, and varies in name at different places. That part next to Cape Corrientes is called Sierra Vuulcan ;* twenty leagues inland is the ridge named Tandil, and at the western extreme is a height called Cayru. Between Tandil and Cayru there ai-e many hills known by particular names, but they are all part of the range above- mentioned ; and it is a remarkable fact, that not only this range, that nearer to Buenos Ayres called Cerrillada, and that of which the Sierra Ventana forms a part, extend nearly in an east-south-east and west-north-west direction ; but that most of the ranges of high land, most of the rivers, and the greater number of inlets, between the Plata and Cape Horn, have a similar direction, not varying from it above one point, or at most two points of the compass. After we became aware * All Indian word, which means ' opening,' or ' having openings.'