As soon as we reached the summit, the lovely valley view was lost and we plunged downward, even more abruptly than we had mounted, along the side of a rapidly deepening gorge.

At the very mouth of this, on a pretty terrace, we came abruptly on the little town of San Lorenzo with palm-thatched huts of brush or cane and well grown hedges of _organo_ cactus.

Here we ate _tortillas_ and fried-eggs with chili.

Immediately on setting out from here we rode over hills, the rock of which was deeply stained with rust and streaked with veins of quartz, up to a crest of limestone covered with a crust of stalagmite.
[Illustration: THE START FROM OAXACA] [Illustration: THE CELEBRATION AT MITLA] The road up to this summit was not good, but that down the other side was _bad_.

The irregular, great blocks of limestone, covered with the smooth, dry, slippery coating, caused constant stumbling to our poor animals.