Albuquerque morning journal., 1908-04-08
BRIEF GEOLOGICAL
HISTORY OF The
TERRITORY

lnr prnr- Mlnlnm q. TIghN

We have said that the ocean is con-
stantly saving away at the coast INES
ana carving the sands and the sed-
iments far out over its iloors. INC
ocean is also the great mother OF Nie.
1t is teeming with animal forms that
sacrete lime skeletons or shells Count
less generations of these forms I'VE
and die, and their skeletons ana shells
accumulate on the ocean lO0r to De
later solidifted into what we know os
limestone rocks of our mountains an"
continents. The ocean door is tnere-
fore a great field of the earth where
the sediments Of the land ana me re-
mains of ocean life accumulate, Ihth
in the history Of geological time WhaI
is at one time ocean floor becomes
land area. These sediments and de-
posits make what are known as STRAIT
afied rocks of the earth. ON every
continent If we measure the thickness
of these rocks we find that II amounts
to hundreds Of thousands OF feet II
must be true, that in the building of
the earth when a good portion of the
earth's surface is below the ocean
then the strataGed rocks are being
formed and when that portion is ele-
waited above the ocean these strata
fed rocks are again being worn down
by erosion and carried back into the
sea to form parts of other sedimentary
beds Such an area, passing the sec
ond time under the ocean, would again
become a field of scdimentatiOn but
| there would be a line of demarkation
| between the first sedimentary beds
/ and the second which would repre-
sent q long land period Of erosion.
/ Such a line of demarkation Is called
| by geologists an lnconformity A plain
/ Of inconformity always represents the
period when the region was above the
sea as a land area.
From the foregoing it must appear
| that the first sediments or rocks to he
formed must be at the bottom Of the
pile and those last formed at the top
20 that we can read the order or
geological history of deposition by the
relative position of the dilterent
s,ratafed rocks.
Geologists have studied most of the
stratafied rocks Of the earth and have
determined the order Of super-posl~
ton and it has been found that these
rocks form a more or less uniform
series from bottom to top, Interrupted
at certain points by great plains ci
i inconformlty
The age when any particular rock
was formed can be determined II we
know its position in this series. There
must have been a time i'm the World
history away back IN inc ptBlHhlhS
Of things, when this present process
had its start This great series OF
stratafed rocks wherever studied on
the earth, is found to rest upon older
rocks which are called igneus because
they are not strataned and show evi-
dence of having crystalized from ~
molten condition Such rocks are
known as GRANTEES, syanites and are
called also crystalline rocks as dis
tingushed from the sand stones.
States, shales, limestones ana marls OF
the sedimentarv series,
For convenience Of reference. this
great series Of sedimentary rocks
resting upon the crystalline rocks be-
low has been divided into what e
known as systems and the divisions OF
time In which each system Of rocks
was made Is known as an era. Tnis
classification Of the rocks is shown N
the accompanying table. II VIII be
understood that wherever any sEa'
TEN of rocks was being formed thai
particular region must have been IN
der the sea 1t Is true that some de-
posits Gre made on the land surface