I will only add the following remarks to this instructive discussion by Professor Ideler. According to Pliny and Solinus, Atlas rises from a sandy plain (e medio arenarum); and elephants (which certainly were never known in Teneriffe) feed on its declivity. What we now term Atlas is a long ridge. How came the Romans to recognise in this long ridge the isolated conical mountain of Herodotus? May not the reason be found in the optical delusion by which every mountain chain seen in profile, in the prolongation of its direction, has the appearance of a narrow cone? I have often seen in this manner, from the sea, the ends of long chains or ridges, which might be taken for isolated mountains. According to Höst the Atlas is covered near Morocco with perpetual snow, which implies an elevation of above 1800 toises, or 11510 English feet. It is also remarkable that, according to Pliny, the “Barbarians,” _i. e._ the ancient Mauritanians, called the Atlas “Dyris.” The chain of the Atlas is still called by the Arabs Daran, a word which has almost the same consonants as Dyris. Hornius, on the other hand (de Originibus Americanorum, p. 195), thinks that he recognises the word Dyris in the Guanche name of the Peak of Teneriffe, Aya-Dyrma. On the connection between purely mythical ideas and geographical traditions, and on the way in which the Titan Atlas gave occasion to the image of a mountain supporting the heavens, beyond the Pillars of Hercules, see Letronne’s “Essai sur les Idées cosmographiques qui se rattachent au nom d’Atlas,” in Férussac’s Bulletin universel des Sciences, Mars 1831, p. 10.