All pretensions on either side founded upon the Bull of Alexander having been formally annulled, the demarcation between the two territories began on the south, at the mouth of a small stream which rises at the foot of the _Monte de Castilhaos Grande_, whence it proceeded in a straight line to the mountains, following their summits to the sources of the _Rio Negro_ and continued to those of the _Ybicuy_; it then followed the course of that river to its junction with the _Uruguay_, skirting the _Uruguay_ upwards until it reached the _Pepiri_, and then the latter river to its chief source; there it left the rivers and took the line of highest ground until it came to the head of the first stream which flows into the _Yguazu_; the boundary then first followed this stream, and then the _Yguazu_ to its junction with the _Paraná_; it went up the _Paraná_ to the _Igurey_, and then up the _Igurey_ to its source; there it once more took the highest ground as far as to the first stream that runs into the _Paraguay_; the water then became the line to the mouth of the _Jauru_, whence the line was to be drawn straight to the south bank of the _Guapore_, opposite to the mouth of the _Sarare_. Wherever the line reached the _Guapore_ it was to follow that stream to the _Mamore_, and then the _Mamore_ to the _Madeira_, and the _Madeira_ to a point half-way between its mouth and the mouth of the _Mamore_; it then struck east and west until it touched the _Yavari_, when it followed that river to the _Amazons_, and went down this great stream to the western mouth of the _Japura_. It ascended this river until it reached the summits of the _Cordillera_, between the _Amazons_ and the _Orinoco_, when it was to go eastward along those summits, as far as the territories of the contracting parties extended. The commissioners were to be careful to trace the demarcation from the westerly mouth of the _Japura_, so as not to touch the Portuguese settlements on that river and on the _Rio Negro_. The Spaniards were to avoid this part, whilst the Portuguese, on their side, were to abstain from ascending the _Orinoco_, and from spreading towards the Spanish territory. The line was to be drawn, without regard to extent of territory, with the object of tracing a distinct boundary. As the limits of the vast territories which were here for the first time separated were imperfectly known to the negotiators on either side, considerable latitude was given to the commissioners at several points. They were to design a map as they traced the limits, and jointly to name all unnamed rivers and mountains; these maps were, respectively, to be signed in duplicate by both commissioners, and were to serve as authorities in case of disputes.