In the interior of South America, between the 2d and 4th degrees of North latitude, a forest-covered plain is enclosed by four rivers, the Orinoco, the Atabapo, the Rio Negro, and the Cassiquiare. In this district are found rocks of granite and of syenite, covered, like those of Caicara and Uruana, with colossal symbolical figures of crocodiles and tigers, and drawings of household utensils, and of the sun and moon. At the present time this remote corner of the earth is entirely without human inhabitants, throughout an extent of more than 8000 square geographical miles. The tribes nearest to its boundaries are wandering naked savages, in the lowest stage of human existence, and far removed from any thoughts of carving hieroglyphics on rocks. One may trace in South America an entire zone, extending through more than eight degrees of longitude, of rocks so ornamented; viz. from the Rupuniri, Essequibo, and the mountains of Pacaraima, to the banks of the Orinoco and of the Yupura. These carvings may belong to very different epochs, for Sir Robert Schomburgk even found on the Rio Negro representations of a Spanish galiot (Reisen in Guiana und am Orinoko, übersetzt von Otto Schomburgk, 1841, S. 500), which must have been of a later date than the beginning of the 16th century; and this in a wilderness where the natives were probably as rude then as at the present time. But it must not be forgotten that, as I have elsewhere noticed, nations of very different descent, when in a similar uncivilized state, having the same disposition to simplify and generalise outlines, and being impelled by inherent mental dispositions to form rhythmical repetitions and series, may be led to produce similar signs and symbols. (Compare Relation hist. T. ii. p. 589, and Martius über die Physionomie des Pflanzenreichs in Brasilien, 1824, S. 14.)