Note {80} — Chapter III · VOYAGE DOWN COAST.

The Sierra del Cristal and the Pallaballa range are, by some geographers, held to be identical; but I have reason to doubt this, for the specimens of rock brought home by me have been identified by the Geological Survey, those of the Pallaballa range as mica schist and quartz; those of the Sierra del Cristal as “probably schistose grit, but not definitely determinable by inspection,” and “quartz rock.” The quantity of mica in the sands of the Ogowé, I think, come into it from its affluents from the Congo region because you do not get these mica sands in rivers which are entirely from the Sierra del Cristal, such as the Muni. The Rumby and Omon ranges are probably identical with the Sierra del Cristal, for in them as in the Sierra you do not get the glistening dove-coloured rock with a sparse vegetation growing on it, as you do in the Pallaballa region.