From this point the frontier shall leave the line of the Makona and be carried in a south-easterly direction to the source of the most north-westerly affluent of the Nuon river or Western Cavalla.
From the north-westernmost source of the Nuon the boundary shall follow the right bank of the said Nuon river down stream to its presumed confluence with the Cavalla, and thenceforward the right bank of the river Cavalla down to the sea.
If the ultimate destination of the Nuon is not the Cavalla river, then the boundary shall follow the right bank of the Nuon down stream as far as the town of Tuleplan.
(The delimitation commission proved that the Nuon does not flow into the Cavalla, but about 6° 30' N.
The river Nuon also is situated 20 or 30 m.
Notably it traced the upper Cavalla, proving that that river was not connected either with the Nuon on the west or the Ko or Zo on the east.
In the Nimba mountains, where also rise the Nuon, St John's and Dukwia rivers.
The Nuon (or Nipwe), which up to 1908 was described sometimes as the western Cavalla and sometimes as the upper course of the St John's river, has been shown to be the upper course of the Cestos.