178 PATAGONIAN EXPEDITIONS: NARRATIVE. 



me. Moreover, considering the jaded condition of my horse and the 

 state of the weather, it seemed advisable to return to camp, where I ar- 

 rived late in the afternoon, somewhat to the relief of Mr. Colburn. Dur- 

 ing the previous evening Mr. Colburn had enjoyed a visit from Dr. 

 Moreno who, with a party of six men and some sixty horses, had camped 

 with him for the night, while en route from Lake Argentine to Chubut in 

 the interests of the Argentine Boundary Commission. I had made the ac- 

 quaintance of Dr. Moreno at Santa Cruz and greatly regretted not being 

 present at the time of his visit. Of all South Americans he doubtless has 

 the most exact knowledge of the geography of that continent and much 

 of it has the advantage of having been gained at first hand. 



I had seen enough of the country lying about Lake Pueyrredon to con- 

 vince me, not only that there was little hope of finding in that region the 

 Pyrotherium beds, which were the real objects of our search, but that the 

 altitude of the Tertiary beds in that vicinity was too great to permit 

 of their being advantageously worked during the present season. 

 I, therefore, resolved to move on northward. The following morning 

 found us on our way north through the sand hills strewn with bowlders 

 toward the eastern end of the broad valley lying east of Lake Pueyrredon. 

 By bearing a little to the eastward we were able to skirt the basalt ledge 

 which outcrops at some distance below the crest of the bluff overlooking 

 the valley and to descend with little difficulty to the level surface of the 

 latter. Once at the bottom, we travelled down the valley until reaching a 

 point where its width, not including the terraces on either side, is much 

 reduced and the wide marsh, which prevails for several miles above, 

 becomes a narrow stream, flowing between rather high bluffs formed of 

 glacial materials. At this point we stopped for a day or two, in order to 

 examine the country to the eastward. 



The bluffs of glacial material just mentioned as occurring on opposite 

 sides of the valley a little below camp, were clearly remnants of a terminal 

 moraine that had at some previous time completely dammed the entire 

 valley. Some eight or ten miles below this the valley was again 

 obstructed by another moraine, which had not been so completely removed 

 as the first one. Above this second moraine was a small lake some 

 two or three miles in length and perhaps half a mile in width. Into this 

 flowed the stream above mentioned. Below the lake the valley contracted 

 rapidly, becoming a deep and narrow basalt canon, seldom more than a 



