Don Luis himself, upon the recovery of Buenos Ayres, repaired thither, and drew up the diary of his interesting journey, which, like those of Villariño and Viedma, and many other interesting papers of the same sort, was thenceforward consigned to oblivion in the secret archivo.[33] The various important political events which shortly afterwards began and rapidly succeeded each other were, however, perhaps some excuse for its remaining unnoticed. In describing the eastern parts of the Cordillera, Cruz says that, at the time he was there, only the volcanoes of Antuco and Villarica were in activity,[34] though the traces of others extinct might be seen in every direction:--the evidences of their ancient eruptions, he says, might be followed for thirty leagues continuously:--he speaks, amongst other volcanic appearances, of hot springs resorted to by the Indians for their medicinal qualities, and says so abundant is the sulphur in all those parts that several rivers are strongly impregnated with it; vast quantities also of bituminous substances are everywhere to be seen, and beyond the Neuquen, he says, there is an abundance of coal.[35] Nor is there good ground for doubting his assertion, since on the opposite side of the Cordillera, in about the same latitude, coal has long been known to exist, and has been occasionally used by the foreign vessels trading with that part of Chile. Near the sources of the Neuquen are mines of rock-salt: in the level lands, also, between that river and the Chadi-leubú, salt may at all times be collected from the surface of the ground, and the intermediate streams are all more or less brackish from its influence. Fossil marine remains appear to abound amongst the lower ranges of the Cordillera which Cruz passed, not only strewed over the surface at considerable elevations, but deeply imbedded in the soil, as might be seen wherever sections were formed by the courses of the mountain-torrents.