Geology of Albuquerque^ N, M. — Hcrrick. 37 
agency of water is proven, while the arrangement of the an- 
gular blocks is like that of glacial boulder clay. The inclina- 
tion of the strata is slight but obviously in a direction radiat- 
ing from the cone of eruption. It would be natural to think 
of volcanic ash or mud but the materials do not admit of this 
conclusion. We are shut up to the view that at the time 
immediately prior to the last eruption of the Isleta crater 
there was a great out-flow of water from the crater, accom- 
panied by explosive fragmentation of pre-existing lava whose 
pieces were either intermittently thrown from the crater to be 
lodged in the pasty mud hurried along by these flows, or 
caught up in the current and after lodging by their own 
weight, finer material was settled about them in the process 
of sedimentation. This mud-flow evidently extended beyond 
the subsequent flow of lava, for such banks are exposed with 
their freight of lava blocks but without the settling and dis- 
tortion resulting from the weight of the lava. Incidentally 
it may be learned that the lava flow followed soon after the 
water, for it can easily be seen that the weight of the lava 
•caused great displacement, especially near the edge where the 
still pliant material was squeezed beyond the edges. The 
upper surface of the sand is baked and browned more than in 
other places, and a great deal of silicious matter has been in- 
corporated into the under layers of the lava, thus proving the 
presence of water at the time of the flow. The finer particles 
of basalt were, of course, carried according to the same law 
as the other ingredients of the material caught up bv the 
gushing waters. Much yet remains to be done in ascertaining 
the extent of the deposits from such floods. That the quan- 
tity of water must have been enormous is plain when we note 
that nearly a hundred feet of the material certainly was de- 
posited over many miles, while the actual thickness may have 
been much greater. (Figs, i, 2 and 3.) 
This instance has a special significance in establishing the 
fact that in connection with the lava flows of the basaltic series 
there occurred great floods of hot water which may well have 
been highly charged with gases and silica. Thus it seems 
possible to account for the great areas covered with silicified 
-wood in the western part of the territory and Arizona. Such 
.great floods would undoul)tedly produce lakes of silicious 
