120 CES ETET KL ORS 
limestone and sandstone as seen in the Sandia range except that 
the deeper sea conditions have expressed themselves in greater 
thickness of limestone. The fossils in the lower part are of 
mid-carboniferous types but pass somewhat gradually into the 
assemblage which we have characterized as Permo-carboniferous. 
Meekela, Terebratula bovidens, Productus punctatus, a large Belle- 
vophon and many other familiar forms indicate an approach to 
the top. Above the measured escarpment but inaccessible to 
our reach is a series of what appear to be yellowish sandstones 
or quartzites which may confidently be referred to the Manzano 
series at the top of the Permo-carboniferous. Northward the 
dip rapidly veers to the northeast and thus the several horizons 
drop below the surface and bring still higher ones than those 
seen at Dog Canyon within reach. About 16 or 18 miles west of 
the main escarpment is a low ridge of hills which prove to 
consist of carboniferous limestone but bearing evidence on their . 
western aspect of the fault which brought the plain down to a 
lower level. This ridge is most instructive in showing that the 
fault was not a single break but by steps or successive faults. 
Wells in the plain to the west all show the existence of the red 
beds both by the presence of salt (often strong brine), but also 
by the red color of the marl brought to the surface. North of 
the outlyer spoken of is a most interesting spring which has 
built up for itself, geyser-like, a mound of some thirty feet 
above the general level from which issues a quantity of warm 
and highly saline water which flows into a depression and, sink- 
ing from view, leaves a large salt and alkali flat. Other similar 
lakes are grouped in the neighborhood. The actual character 
of the deposit is generally masked by a calcareous marl of white 
or gray color which forms a crust over the entire plain and is 
highly charged with salts except at the immediate surface. 
But passing northward and observing several other saline 
springs similar to the one described, the route carries us through 
the intensely modern ‘‘boom” town of Alamagordo with its 
great sawmills fed from the Sacramento Mountains by a spur 
railroad and the equally typical old Mexican town of Tularosa 
