National Geographic : 1919 Apr
HERE UDJ ASSARU IS SEEN IN THE DISTANCE (SEE PRECEDINGPAGE) This photograph is of very great importance, because it contains the history of this entire Troglodytic region. Ifi the foreground we seethe naked, barren pumice-stone, with spots of overlying lava, or peperine. The disintegrated atoms of pumice-stone areswiftly swept away bythe rain-water to the valley below, so the upper country always remains quite barren. The process of erosionisclearly seen here. Note the presence of cones even at this elevation, for a beautiful cone stands on the very summit of the ridge at the left of Udj Assarii aid five other fine ones areto be seen on the right of Udj Assaru. This means that an almost inconceivable amount of erosion has taken place here. Itmeans that the original level of the plateau corresponded approximately with the tiptop of Udj Assarii itself, and that all the rest ofthe plateau has rotted off and been washed away. Accordingly, the cone formations are not of comparatively recent date, as some have contended from the fact that noancient writer mentions the cones. On the contrary, this plateau was in existence in most remote antiquity.