National Republican. (Washington City (D.C.)) 1872-1888, 1874-04-23
THEACADEMY OF SCIENCE
[Contin..ed from sseond paqs. ]

IContinped from second pegs.l
along which, and standing shout for score o
miles In eyerf direction, are volcanic cones, lis Il
mum Der. 80, >
The Indian name for this group IL U-in-kare,s
the mountains where the pines stay, and thi
lU-in-ka-rets) is the term by which they or.
Northern Arizona who live In sight Of the noun
tains and who have daily uss for soma mamie. Al
the names given by Wbippis sed Ives vsr'
dian name has been adopted.
The position of every cone IN the group ha.
been detsrmined IN the secondary triangulatioI
Of this region on scale Of two inches to thu
Other mountains nave boon added to the gen
eral stock Of GEOGRAPHIC knowledge, and many
which had been seen by other travellers, have
maps. ~ sL -
Such is a summary of the geographic wori
We turn now to the geological work. A run.
ming section has been made from q point twelve
miles above Green River station, following Green
virgin, distance of more than thousand miles
This section is unbroken for the entire distance
the rocks were exposed In escarpments varying
from one hundred 10 more than SIX thousand feel
In altitude. Perhaps no other section has ever
been made, the elements Of which are OF such
magnitude: In this region OF country, as fast as
loose sands are washed away 80 that the escarp-
ments are clear Of soil and vegetation, and under
these circumstances 10 was found possible to col
lect o vast amount Of details. Again, the geolog.
ical structures OF tho country Is very complex.
Great and minor folds, great and minor fauite
and greet and minor non-conformities are found,
50 that the sections are also exceedingly complex
The Uintsh mountains, having an easterly and
westerly direction stand the course OF Green
river i've here We have great fols, the a1,ielinal
tion, and total displacement Of about q 900 feet,
80 that IN going down the river from Green River
sion Of beds 1000 feet In thickness, including
rocks from the moicene tertiary to the sllurian.
On the north flank Of the range we
talline achists. :. / considered them to belong
to- the same horizon as the uncomfortable
beds immediately below the carboniferous rocks
could trace the netamorphism literally into
these rocks through series somewhat like this
gneiss plcated sehIsts visns or quartz, quantities.
and regularly-bedded sandstones. In that por-
ton Of the canon where no metamorphism 10 seen
obtained eleven thousand feet Of these beds. At
this point our work overlaps that done by parties
directed BY Clarence King. Mr; Emmons, 1 be-
derlie the sandstones, and obtained section OF
only two or three thousand feet of sandstones d.
The grand fold OF the Uintah mountains Is
greatly complicated by a series Of transverse and
oblique minor folds, some Of which are anticllnal
others monoclinsl. Our general section on the
river, with number Of minor sections In various
directions, together with tho colored geological
map Of the mountains, Will explain this complex
system Of corrugations; and what have consid-
cred Of equal Importance, the progress and extent
of erosion which is here exhibited on vast scale
since the region was LETT by the retiring sea.
Going on south we pass synelinal trough
Uintah river, which comes down from the
Wasstch mountains on the west, and by the val
ley of White river, which comes down from the
Rocky mountains on the east.
Still continuing to the south we ind rocks dip
ping to the north, and in our progress down the
river We pass succession OF underlying beds
foot Of the Canon Of Desolstion then 500 feet Of
cretaceous rocks OF the foot Of Gray canon nearly
1000 feet Of the jurassio, and an equal amount Of
once more enter beds OF carboniferous age.
In descending through Saltwater canon, Cata-
ract canon and Marrow canon, We 20 toward the
axis OF great fold marked BY the Sierra La Sal.
sans slope At The end Sf Marrow canon, and again
enter beds Of triassic age.
From this point to the southern extremity Of
the great system of southern plateaus, marked by
line Of efuptive mountains Of which San Fran
cisco mountain Is the eliminating peak, the gen.
eral dip of the formation is 10 the NORTH extend
Colorado and westward to the foot Of the Pine
Valley Mountains, but this general slope Is
greatly modified by another, and doubtless later,
These dispiacements are either faults or mono
clinsl folds. ! shall recur to them again.
Descending the Colorado through Glen Canon,
ago developed 70 thickness Of about 500 feet.
On the way We cross an abrupt mono-clnal fold,
the drop Of which Is to the east and the total dis
At the foot OF this canon We cross another Of
these folds, the drop OF which is also to the east
Here we enter Marble Canon, . chasm cut
4 hrnrH frh ko 0f "a Nh mil n
The course Of the river Is nearly south, and the
dip Us above stated is to the north, that at the
foot We have passed through about 800 feet OF
Canon we are going In the general direction OF
the strike Of the beds, but there are great dis
placements due to faults, which, back from the
river, are, In many places, mono-cinal folds. The
summit of the Grand Canon is every where tho
summit Of the Carboniferous, which is from 1000
to $500 feet in thickness; but the gorge Is some
times more than 1900 feet deep, and at
these points we obtain a succession Of
sections OF uncomfortable shales, sandstones
and limestones, the greatest Of which gives Us o
little more than 10000 feet OF beds. These are
traTsrsed by dikes Of trap or green stone, and
irregular beds of the same eruptive material are
found in places between these uncomfortable
PSoyisiOpaiiy caI1 these sedimssta1V
Devonlan and Slluriau. Still underlying these
We find an extensive series Of motamorphic crys-
talline schists, in some places yet showing faint
traces OF the original qualification, but usually
these are so degraded that the total thickness Of
the beds cannot be determined, or at least we
were unable to do so. In places they constitute
These beds are traversed by. bikes Of granite,
and beds Of granite are found.
believe these beds to be intrusive, and hence
complete. An extensive period Of erosion sepa-
rates these schists and GRANTEES from the over
lying Silurian and DevoniRn rocks.
nsi
Followed bY pllcatton, erosion, assuring and
eruption. Again we have an invasion Of the sea
which remains until 1000 feet OF shalss, sand,
followed by dry land period, marked n some
places by at least 10000 feet Of erosion, and ac-
companied by plicstion. assuring and eruption.
until s rcfs Of "aSS a 81 s sss
dspo.sd EhI perhaps some Fsfsisre SsS Of
feet Of beds were formed. All this is succeeded
by long period Of erosion, In some places strip
ping on the whole 1000 feet Of later beds and In
the gorges, where the streams have made greater
the underlying rocks OF Devoniau and Silurtau
nge and still deeper into the schlsts and grantees
Such are some Of the facts brought blight In
the great section made from Green river station
TO the mouth Of the Rio Virgen.
You have already seen In the account given of
the geographic work that q much greater length
Of time was expended in the studies made on land
than In those made on the river. ~
A geological section has been made from the
Grand Wash to the Vcrruillion cliffs west Of
Marble canon near the parallel Of $50 30, another
from the Colorado river west to the Pine Valley
mountains near the parallel Of SO 30, another
rom the Sewer river east across the Wasatch
plateau and still on to Green river. Ono has been
made along the course Of the Paria from its source
n the Pauns-a-gunt plateau to its mouth, includ.
ng rocks from tertiary through triassic age to
.he summit Of tho earboniferous. Another has
been made from the Pauns-a-gunt plateau south
slong the course Of the Kanab to its mouth repre-
'enting rocks OF ages extending from the tertiary
% the base Of the carboniicrous still another
CUNT plateau down the Rio Virgen to its mouth
embracing series or rocks from tho tertiares
through the earboniferous, deyonian and silurian
INTO the schists.
In addition to these general or running sections
numbers OF vertical sections have bean made for
The monocltpal folds, and faults have been
raced along their courses, and the material has
leen collected for the construction OF q series of
diagrams TO represent tho eyer-ohangi1g throw or
lrops OF these folds and faults with frequent trans
Terse sections to represent the eyer-changuy char
ofthese displasements =.
After the sea had len Ibis region the last tiuo
md during the progress OF folding eruptive matter
las been poured out, traehites and rhyolites at
irst, then basalts.
Those erdptIye beds have also been studied
md mapped. But our work In structural geology
las not peen confined TO the making Of these see
ionsi the surface distribution OF the various
ocks has been noted, so that we shall be- able TO
dior on the map every township or land contained
While much time has been devoted to the .truc.
ural geology Of the country we have not neglected
he p2Ieontology, and We have had such success
collecting fossils rs to be able to refer all these
ocks 10 tho grand groups which have been estab-
shed on archaeological basis In the general
eology Of North America.
h n ind onf fhoi