1891.] A Recent Lava Flow in New Mexico. 525 
surrounded by extensive deposits of gypsum. These desiccated 
lake remnants, together with the beaches and extensive lake-bed 
deposits, conclusively prove the former existence of a lake in this 
interior basin, and the freshness of the deposits points strongly to 
the conclusion that the lake is of recent date. 
Both the mountains and foothills show signs of much more 
powerful erosion than seems possible under the present conditions 
of rainfall. This would not be so strongly stated if it were not 
for the fact that well-defined valleys, now somewhat clogged, 
extend well out into the lake deposits, much farther than the 
present streams succeed in going. It isin one of these valleys 
that the lava flow under consideration is found. 
The cone which is at the northern end was not visited, but I 
was informed that it was fresh and had every appearance of 
extreme youth, and this must be so from the evidence furnished 
by the lava itself. Near the cone the lava spreads out over con- 
siderable territory, but farther south becomes constricted, and at 
the southern end again broadens out, conforming in a measure to 
the shape of the stream valley which it fills. The elevation at 
the northern end is 5,360 feet, while at the southern end it is 
4,100 feet. Viewed from either side of the basin the flow isa 
striking object, forming as it does a jet-black stripe in the monoto- 
nous brown of the surrounding plain —the brown so characteristic 
of the parched soil of an arid country. No bushes or grass have 
found life possible upon these black basaltic rocks, no soil has 
formed, and so the lava stands out with all its native blackness. 
Some moss, cacti, and a few stunted shrubs are the only forms of 
vegetable life that have as yet found a footing on this inhospitable 
rock, and these only in a few nooks and crevices. as 
` The present surface is undoubtedly the surface of original 
cooling, and one might almost be justified in the belief that the 
cooling took place but yesterday were it not for the evidence to 
_ the contrary furnished by the scanty vegetation. The flow, 
made up of rolling masses of a vesicular, ropey lava, very pen 
broken and fissured. Everywhere on the floor the basalt has 
been broken into splinters and boulders, which are piled up in lit- 
tle hillocks over almost every part of the surface. So ragged is 
