But if prehistoric life existed upon the plateau it was not superabundant, for we had no further glimpse of it during the next three days. During this time we traversed a barren and forbidding country, which alternated between stony desert and desolate marshes full of many wildfowl, upon the north and east of the cliffs. From that direction the place is really inaccessible, and, were it not for a hardish ledge which runs at the very base of the precipice, we should have had to turn back. Many times we were up to our waists in the slime and blubber of an old, semitropical swamp. To make matters worse, the place seemed to be a favorite breeding-place of the Jararaca snake, the most venomous and aggressive in South America. Again and again these horrible creatures came writhing and springing towards us across the surface of this putrid bog, and it was only by keeping our shotguns forever ready that we could feel safe from them. One funnel-shaped depression in the morass, of a livid green in color from some lichen which festered in it, will always remain as a nightmare memory in my mind. It seems to have been a special nest of these vermins, and the slopes were alive with them, all writhing in our direction, for it is a peculiarity of the Jararaca that he will always attack man at first sight.