The valley of the Huatanay River is divided into three parts, the basins of Lucre, Oropesa, and Cuzco.  The basaltic cliffs near Oropesa divide the Lucre Basin from the Oropesa Basin.  The pass at Angostura, or “the narrows,” is the natural gateway between the Oropesa Basin and the Cuzco Basin.  Each basin contains interesting ruins.  In the Lucre Basin the most interesting are those of Rumiccolca and Piquillacta.

At the extreme eastern end of the valley, on top of the pass which leads to the Vilcanota is an ancient gateway called Rumiccolca (Rumi = “stone”; ccolca = “granary").  It is commonly supposed that this was an Inca fortress, intended to separate the chiefs of Cuzco from those of Vilcanota.  It is now locally referred to as a “fortaleza.”  The major part of the wall is well built of rough stones, laid in clay, while the sides of the gateway are faced with carefully cut andesite ashlars of an entirely different style.  It is conceivable that some great chieftain built the rough wall in the days when the highlands were split up among many little independent rulers, and that later one of the Incas, no longer needing any fortifications between the Huatanay Valley and the Vilcanota Valley, tore down part of the wall and built a fine gateway.  The faces of the ashlars are nicely finished except for several rough bosses or nubbins.  They were probably used by the ancient masons in order to secure a better hold when finally adjusting the ashlars with small crowbars.  It may have been the intention of the stone masons to remove these nubbins after the wall was completed.  In one of the unfinished structures at Machu Picchu I noticed similar bosses.  The name “Stone-granary” was probably originally applied to a neighboring edifice now in ruins.

On the rocky hillside above Rumiccolca are the ruins of many ancient terraces and some buildings.  Not far from Rumiccolca, on the slopes of Mt.  Piquillacta, are the ruins of an extensive city, also called Piquillacta.  A large number of its houses have extraordinarily high walls.  A high wall outside the city, and running north and south, was obviously built to protect it from enemies approaching from the Vilcanota Valley.  In the other directions the slopes are so steep as to render a wall unnecessary.  The walls are built of fragments of lava rock, with which the slopes of Mt.  Piquillacta are covered.  Cacti and thorny scrub are growing in the ruins, but the volcanic soil is rich enough to attract the attention of agriculturists, who come here from neighboring villages to cultivate their crops.  The slopes above the city are still extensively cultivated, but without terraces.  Wheat and barley are the principal crops.