Continue heading for the north for the RP39, overcoming the river Uspallata for the long one AI foot of the mountain range fences, amid a landscape of colorful relief and stocky vegetation, distant trenches of eucalyptuses and poplars belonging to the cattle stays of Yalguaraz are sighted. San Alberto and The Tambillos.
After the kitchen knives of the Tiger it is entered to the yalguaraz marsh, wide plain where they drain numerous torrents (basin endorreica),
that they are absorbed by the underground and gift place to extensive coirón pastizales. Then, it arrived to the archaeological place The Tambillos, on the one on the way to the Inca. There are informative posters and mirador to see the ruins.
The point is in the limit interprovincial but high of the itinerary, where a spectacular view of the mountain range sanjuanina opens up, with its hill Mercedario ( 6.770 m ) and the Seven Picks of Ansilta.
From the limit the RP412 cheats pavement in not well state. It crosses the marsh of the Ostriches and then the pampas The Leoncito, a vast plain desértica and basin that the incredible Barreal forms Blanco, used as natural hint for practical of carrovelismo (windcars).
This territory is an important astronomical reservation, clerk of the Secretary of State of Science and Technique. Toward the east it glitters the dome of the Observatory The Leoncito, to which you consents for a deviation of 17 km , signalled, to the right of the road (descripto in the Walk To Barreal Blanco and the obervarorios ).
Near 20 km the route arrives later on to Barreal.