ANCIENT INDIAN TRAILS. 119 



igneous materials, which now cover to a depth of many feet the surround- 

 ing country, were ejected from numerous fissures and poured out over the 

 surface of the plain I How far had these phenomena been responsible for 

 the extermination of that rich and varied fauna that had lived and flourished 

 in such abundance in Santa Cruzian times? While engaged in collecting 

 their remains. I had noted that for the most part, judging from the ana- 

 tomical characters exhibited by their bones and teeth, they had been well 

 adapted for sustaining themselves in the midst even of only fairly favor- 

 able environments. What then had caused the wholesale destruction or 

 disappearance, not only of genera and species, but of entire families, and, 

 in some cases, even orders of these animals? Had their extermination 

 been gradual, or had they been overtaken and completely destroyed by 

 some sudden catastrophe? If the latter, was fire or water the destroying 

 element? These and many other similar questions presented themselves 

 for solution, but I had to confess my inability to arrive at a satisfactory 

 answer to any of them, and thrust them aside for a more definite though 

 not more interesting occupation, which, however, would be followed by 

 certain tangible results. 



On the twenty-third of January we started up the Rio Chico from our 

 camp near Sierra Ventana. We soon entered the great basalt-enclosed 

 caflon through which the river flows for a distance of perhaps one hundred 

 and fifty miles on its way from the Andes to the Atlantic. Day after day 

 we pursued the various meanderings of the stream, following the old 

 Indian trail which for centuries had formed the chief highway of com- 

 munication between the Indians of northern and southern Patagonia. 

 Although now seldom used, the many paths worn deep into the surface 

 of the valley, bore mute, but unimpeachable testimony as to the amount 

 of travel that had frequented this highway in former times. While the 

 broken or discarded tolda poles and other accoutrements, scattered by the 

 wayside, plainly bespoke the character of the travellers, by whom the trails 

 had been worn throughout repeated journeyings across the unknown and 

 uninhabited country, lying between the Rio Negro, on the north and the 

 Santa Cruz on the south. At times our road would stretch for miles over 

 the level, grass-covered valley. Then for a short distance we would be 

 compelled to resort to a dangerously narrow trail, skirting the side of some 

 cliff as the river made a sharp bend and, encroaching upon the valley, 

 rushed along over whirling rapids, or though deep quiet eddies at the foot 



