112 ^ PATAGONIAN EXPEDITIONS : NARRATIVE. 



and it expanded into a broad, level basin-shaped valley with numerous 

 fine springs of water and a bountiful supply of grass. By the side of one 

 of these springs we camped for the night, putting our horses to graze 

 in the valley beneath. A fair conception of the nature of the basaltic 

 canons of Patagonia can be had by inspecting the accompanying illustra- 

 tions in Figs. 7, 8, 9, 10, made from photographs taken by the author. 

 Walking about this little valley during the evening and examining the 

 various pools and springs to ascertain what they contained of animal 

 life, I was struck by the great abundance and character of a species 

 of Chara with which every water hole and spring was literally filled. 

 In collecting this plant for the herbarium I noticed that it was extremely 

 harsh and brittle, even while still wet and fresh from the pool. So 

 highly charged was it with mineral matter (CaCO 3 ) that it was difficult 

 to separate and properly arrange the different specimens in my drying 

 papers without their breaking up into little bits. On using the water it 

 was found to be very hard. The water of these springs was so highly 

 charged with carbonate of lime, that all the pebbles and rocks lying about 

 the water's edge were coated over and often cemented together with a 

 thick covering of that mineral. Following the course of several of these 

 springs to the bed of shingle and the basaltic platform above, I found the 

 basalt full of cavities filled with crystals of calcite. This explains how 

 the water of the springs beneath had become so highly charged with car- 

 bonate of lime. Over this little valley and about the foot of the basaltic 

 cliffs, which for the most part surrounded it, there grew a number of plants 

 which I had not observed elsewhere, and the remainder of the evening 

 was passed in securing and pressing a set of these as additions to our 

 botanical collections. 



Early on the morning of the sixteenth we resumed our journey. We 

 were not long in climbing the slope which lay between us and the broad, 

 high pampa above. When we had gained the surface of the latter, we 

 laid our course in as nearly as possible a due northwesterly direction. 

 Travelling for a distance of from twenty-five to thirty miles across this 

 pampa, the surface of which sloped gently from northwest to southeast 

 and was entirely unrelieved by either elevation or depression, at about 

 one o'clock in the afternoon we came suddenly and unexpectedly to the 

 crest of a high escarpment overlooking the valley of the Rio Sheuen, or 

 Chalia, which lay some two thousand feet below. Immediately in front 



