842 TRANS. OF THE ACAD. OF SCIENCE. 
and rege the entire See of the “Jornada.” As will 
hereafter be seen, it composed principally of upheaved — 
strata of dark gray, bla ue and black sub-crystalline lime- 
stone, dipping west at bce — Dante these moun- 
boy h gener: direction and are apparently a 
ontinuous with the Organ pniighs wi ith hid they have been — 
re are totally net... iI spect is there the 
sights resemblance between them, one being composed ak 
most entirely of sedimentary strata, and the other mainly of — 
Seuyiive rocks. The cause of the upheaval of this portion of 
the Organ Mountains is rendered fully apie by a chain of 
low igneous hills which have been traced extending oe : 
