foothills parallel to the lofty range towering above. Often were they menaced by the savage denizens of this remote fastness, and occasionally Tarzan glimpsed weird forms of gigantic proportions amidst the shadows of the nights.
On the third day they came upon a large natural cave in the face of a low cliff at the foot of which tumbled one of the numerous mountain brooks that watered the plain below and fed the morasses in the lowlands at the country's edge. Here the three took up their temporary abode where Tarzan's instruction in the language of his companions progressed more rapidly than while on the march.
The cave gave evidence of having harbored other manlike forms in the past. Remnants of a crude, rock fireplace remained and the walls and ceiling were blackened with the smoke of many fires. Scratched in the soot, and sometimes deeply into the rock beneath, were strange hieroglyphics and the outlines of beasts and birds and reptiles, some of the latter of weird form suggesting the extinct creatures of Jurassic times. Some of the more recently made hieroglyphics Tarzan's companions read with interest and commented upon, and then with the points of their knives they too added to the possibly age-old record of the blackened walls.
Tarzan's curiosity was aroused, but the only explanation at which he could arrive was that he
