sharp descent, and found ourselves upon an ugly piece of limestone or sandstone rock, which soon, to our surprise, we found replaced by a solid mass of obsidian.  The cochero, says that the place is known as itzlis—­the obsidians, the knives.  It was 2:30 when we reached Aguazotepec, where we called upon the presidente, and engaged a mozo, for a peso, to convey our instruments the balance of the journey, as we were completely tired out with carrying them upon our knees.  We also arranged with that official to forward the balance of our stuff to Huachinango the following day.  We also arranged to pay for horses from Aguazotepec to Huachinango.  Having eaten an excellent dinner, when ready for resuming our journey, we discovered, with surprise, that the stage was still our conveyance to Venta Colorado, only a league from Huachinango.  There we were to secure the animals for which we had paid, though we were warned that only three could be supplied.  Manuel and Louis at once tossed coins to see which should ride first.  Although we had paid the full cost of the coach, two other passengers were crowded in upon us, and the man, for whom we had paid the peso to carry our instruments, ran alongside the coach on foot, throwing stones at the mules, while we had again the pleasure of carrying the instruments and boxes on our knees.  The country through which we rode was much as before.  For some time we passed through a fine pine forest; then we made a deep descent into a valley, at the bottom of which flowed a large stream, which was bridged by a grand old structure of stone and cement.  This descent, and the opposite ascent, we were obliged to make on foot, as the approaches were bad.  We have been impressed strongly with the fact that everywhere in Mexico the worst bits of road are those which, in old Spanish days, were handsomely and well paved; and which, during the disturbed period of the early Republic, were neglected and allowed to go to decay.  It is depressing to see so many evidences of past magnificence and present poverty.  It was almost dusk when, after skirting the edge of a deep gorge, we reached a piece of bad road, where the coach with difficulty made its way, with frightful jolts and pitchings, till we drew up at Venta Colorado.  Here the coach was finally abandoned.  Our animals were packed and mounted, and after fussing and quarreling with our ugly cochero as to whether he or we should carry the bulk of our baggage, we started.  The distance was not great.  It was down hill, and we had to pick our way with great care over the rough road, filled with loosened and separated blocks of ancient paving.