GEOLOGY OF THE WHITE SANDS OF NEW MEXICO 119 
Socorro county which has proven such an effectual barrier to 
communication between the Rio Grande valley and the growing 
region of White Oaks. South of the ma/ pais is a great white 
sea on which one can fancy the glint of white-caps. Sucha 
body of water being out of the question the uninstructed observer 
would surely think himself the victim of a mirage but we 
recognize in the snowy area the tamous white sands. Curious 
and conflicting stories are current respecting the area but the 
truth is not less interesting. We had already been forced to the 
conclusion that the true origin of the saline and gypsum beds is 
to be sought in the red series above mentioned. It seemed at 
first, however, that the geological relations would prove baffling. 
Rising abruptly from the level plain on its eastern side are the 
foothills of the Sacramento range near which pass the trains 
upon the newly-finished El Paso and Northeastern railway. 
The escarpment is nearly perpendicular and the dip is very 
slight and to the east. The bottom of the sedimentary series is 
not reached, at least in this vicinity, but it is evident from a 
comparison of this with the western escarpment that the base 
is not far distant. The section is given in detail below but we 
were very fortunate in coming upon a locality where the lower 
portion of the section is fossiliferous About 560 feet from the 
base, at Dog Canyon, some 12 miles southeast of Alamogordo isa . 
band of crinoidal limestone which, together with the gray lime 
and quartzite above it, contains numerous, though poorly pre- 
served fossils. Among these enough forms were identified to 
determine the limestone as Burlington. As nearly as we could 
determine the Burlington is represented by at least 250 feet. 
Several intercallary sheets of igneous rock (diorite, with por- 
phyritic hornblende) penetrate the strata and obviously connect 
with a boss farther east and higher upthe canyon. The influence 
of the intrusive may account for the amount of chert seggre- 
gated in this portion of the section but, for whatever cause, the 
limes are chiefly highly silicious and quartzite has replaced 
former limestones. Above the Burlington, which is entirely 
absent farther north, is the entire series of Coal Measure 
