1 84 Bulletin of Laboratories of Denison University. [Voi. xi. 
pies a place in the loess exposure on the east side. This gravel 
may be found in some places on the west side on top of the 
bluff mentioned. This gravel bed evidently marks the period of 
high water and rapid erosion for it is deposited very irregularly 
in eroded areas of the loess. It may be conjectured that this 
was a period of melting of glacial ice to the northward. The 
materials of the gravel can be traced to the northern ranges and 
adjacent Tertiary and Cretaceous strata. The Albuquerque 
marl occupies the upper portion of the mesa over much of its 
surface and has many of the characters of the Tertiary marls of 
the Albuquerque mesa. It is however less regular and maybe 
supposed to be composed of the material eroded from that for- 
mation during a period of comparative quiet. It may be traced 
southward along the river to the vicinity of La Joya. 
The Sandia mesa receives a great deal of float from the 
mountains and accordingly, near the foot of the range there is 
an abrupt increase in the angle of inclination marking a talus 
portion. But even at a distance the coarser elements evidently 
derived from this source are more abundant at the surface than 
in the deeper portions. The eastern or major fault line forming 
the monocline of the Sandias runs at no great distance from the 
base of the mountain escarpment, as is shown by the fact that at 
a distance of from half a mile to a mile west of the immediate 
foot hills there appear portions of the formations above the Car- 
boniferous either nearly horizontal or inclined gently to the east. 
One such fragment is composed of earthy limestone impregnat- 
ed with calcite and lies about a mile north of the mouth of Tije- 
ras canon but does not appear upon the sheet. Another nearly 
west of the mouth of Hell canon consists of red sandstone ap- 
parently of upper Permian or Jura-triassic age. The total 
throw of this single fault must have been at least 4000 feet. 
The small spur of schists which projects into our sheet from 
the east should be considered in connection with the Sandia 
range of which it appears to be the offshoot. It is in reality 
cut off from the main range by the great Sandia fault and is to 
be regarded as a resultant of localized metamorphic activity inci- 
dent to that great seismic disturbance. The material of this 
