Meridiana by Jules Verne

All pretext for quarrelling being now removed, the Colonel and Strux, somewhat rancorous at heart, recommenced their joint labours. About five miles to the left of the gap made by the conflagration, rose an eminence which would serve as the vertex of a new triangle. When the requisite observations were complete, the caravan set off across the burnt forest.

The road was paved with embers. The soil was still burning, and here and there smouldered stumps of trees, while a hot steam rose around. In many places lay the blackened carcasses of animals which had been unable to make their escape. Wreaths of smoke gave evidence that the fire was not yet extinct, and might still be rekindled by the wind. Had the flames burst out again the caravan must inevitably have been destroyed. Towards the middle of the day, however, it was safely encamped at the foot of the hill. Here was a mass of rock which seemed to have been arranged by the hand of man. It was a kind of cromlech -- a surprising erection to find in that locality -- resembling the structures attributed to the Druids, and which ever furnish fresh interest to the archeologist. The most credible suggestion was that it must be the remains of some primitive African altar.