MUD-STREAMS. 133 



depth. Moreover, the surfaces of the larger of these were not always of a 

 character to reveal their true nature. On the top there would be formed 

 a half-hardened crust, rigid enough to support bowlders of considerable 

 dimensions. The presence of these, together with the generally level ap- 

 pearance of the surface, would make it seem to offer a safe highway much 

 t be preferred to the steep and slippery slopes on either side. Hardly 

 would the poor horse leave the difficult incline and take to this compara- 

 tive!) level highway, when he would break through the treacherous crust 

 and find himself floundering in several feet of thick, sticky mud, from 

 which he was frequently quite unable to extricate himself, until after being 

 unsaddled, and then only with the greatest difficulty. These streams of 

 mud were phenomena previously quite unknown to me, but it needed 

 only a few experiences with them to teach me to recognize and avoid 

 them. I afterwards observed that they were actual mud-streams, com- 

 mencing in many instances near or at the summit and gradually aug- 

 menting in volume, by the accession of occasional tributaries, until, at the 

 mouth of the main gulch, they spread out in a broad, fan-shaped mass 

 upon the surface of the valley like the termination of a miniature glacier. 



After a long climb, attended by many interruptions, I reached the sum- 

 mit, on the surface of which I found growing a few scattered Alpine plants- 

 For the most part, however, it was quite bare. From my elevated position 

 I could look off over the surface of the great, black, basalt-covered plains, 

 which lay to the east. Looking to the northward, down the valley of the 

 little stream on which we were camped, I could see between the mountains 

 in the distance, the broad, deep valley of a great river which I knew had 

 not been previously discovered. Beyond this lay a broad, circular basin, 

 enclosed by the most rugged and picturesque mountains I had ever seen. 

 Through the deep caAons, eroded in their precipitous slopes, numerous 

 glaciers descended from their snow-clad summits to the basin below, while 

 a considerable river flowed from the front of each of these glaciers out 

 across the valley to unite its waters with those of the larger stream, which 

 I had already decided to call Mayer River in honor of General Mayer. 



To the south the ridge expanded into a series of bare, rounded hills or 

 hogbacks. These had a general easterly slope and gave rise to a number 

 of small brooks, which united below to form that fork of the Rio Chico by 

 which we had entered Mayer Basin through Shell Gap. The surface was, 

 for the most part, swampy and on the lower slopes a low trailing shrub, 



