200 GEOLOGY OF THE HIGH PLATEAUS. 



given by the first view. The surfaces of the fragments are not affected 

 by weathering to any notable extent, and it is only by comparison with 

 surfaces fractured by the hammer that we can find an assurance of 

 an exceedingly slight impairment of its original freshness. No doubt 

 this is largely due to the fact that this portion of the mass is not in the 

 slightest degree vesicular. In other parts of the coulee highly vesicular 

 fragments were encountered; but where I first approached it every stone 

 was as compact as a dike. But even the vesicular specimens show so 

 little weathering, that it is hard to believe that this eruption is as old as 

 the discovery of America. Such appearances, however, may be very de- 

 ceptive. I am not aware that there is any authentic record of a volcanic 

 eruption within the present limits of the United States, though it is quite 

 possible that a number of them have occurred since the conquest of Mexico 

 by Cortez. In this region it may have easily escaped the chronicles of the 

 Spanish priests, even if such a dire event had occurred only a hundred 

 years ago, and two hundred years would have destroyed all reliable tradi- 

 tion of it among the Indians.* This basalt came from a vent situated about 

 3 miles southwest of Panquitch Lake, and from the same source flowed a 

 considerable number of large streams all presenting the same appearance 

 of recency. An attempt was made to reach the crater, but the climbing 

 over the rough angular blocks piled up in the worst conceivable confusion 

 proved to be so perilous, that after several misadventures it was abandoned. 

 From surrounding eminences several overlooks were obtained, from which 

 it was inferred that there are several vents clustered near each other, and 

 from three of them at least there have been a number of eruptions. Noth- 

 ing like a cinder-cone, however, was distinguishable. The lavas appear to 

 have reached the surface and overflowed like water from a spring, spread- 

 ing out immediately and deluging a broad surface around the orifice, and 

 sending off into surrounding valleys and ravines deep rivers of molten rock. 

 One flood rolled northeast towards Panquitch Lake, but came to rest before 

 reaching it. A second flowed eastward down a broad ravine situated about 

 3 miles from the lake. The largest streams went to the southeast into 



* There is said to be a tradition among the Mohave Indians that their ancestors were driven out 

 of Central Arizona by volcanic eruptions, and though very recent basalts are found there, many cir- 

 cumstances combine to oppose such a tradition even if there be one. 



