New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1857-08-21

tertiary N Iowa.
Pioi GuYeT followed On The PhyeioM Structure
Sf the Continent If AhI'a
Hnberto Prof Ri,ters theory has been accepted,
but tie researches Of Barth, Vosei, Ly ngstoa and
others, have put q new face upon this subject.
Africa May b. divided into two grand portions, tnh
huge mas. wing Forth Of the parallel Of deg n COO.
s,itutpg High Africa and the grat triangle froto ii It
line south constituting Low Anica. The structure 81
Low Afjco hiss been corShered one yas honoSeneoo'
tsble-ald This idea must DUw b. modified. huss-
ger, On Austrian ssyant, has made known two long
eLnps Of neataiLs, one near the eastern coat anu
tie ctteI rear the western. with wei bo"" -
tween. We thus have two directions ara Two up
bSa,al The eastern reaches po!ihery 70 Abyosma,
where it breaks into irregular ranges No region ~
Low Afric& properly bc conndered as o" E'tr, 81,
ger giving general elevation OF wv ieet. baliH
and Vcae give US lotions Of the porth, az Li'-
,ncstou Dalton, Andrews and others Of the touth.
South Africa TO- on the whole, high tsOc-Ieod.
Tie certer u that part OF tbs continent Is uepeSs
sion which rurs noIihery, and finally JOINS the Nae
valley The eastern swtn Of Low Africa is DOT e.
acly mourtain chain, bat the vast main swell oil the
CONTINENT GO to 20 800 rect IN elevation ina. on
I The western border is ZONE 500 feet lower lhey
| both up TO nearly the Fam. LATITUDE nortn,-.o
Where the western swell falls of, Bath found vast
plain with mountains; the eastern swell runs on into
| the Arabian nour tsns The African continent may
| be ccrtldeIed a hollow continent.
In Northern Africa the grand elevations have an
eaterly and westerly course, aud Sahara Is III fact
vast table Lard, 800 feet above the sea level.
| South Ct Sahara we find Lake Ichad, elevated but
about SEQ feet. Moth OF Sahara We nave inc Auas
chain eouh the Kong mOuDtans; and the Desert,
though dverrifed by mountains and hhs, Is grand
depr.ssion across the continent
HE slopes Of tie Atlas fall off south to very deep
dep,t ssob rising again 10 the level OF Sahara. The
gieat 1orthern chain Of RIGA is in fact continuation
OF the vast ges Of Himaaya passing to the west
ward and across Southern Europe.
| Africa exhibits the form and cOniiguGaton ansng
from the compound Of the two great upheaving ac-
tons which sevetally produced North America and the
Continent Of Europe and Asia-tbe north ano south
action in Lower Africa, the east and west IN the
Northern portion The great correspondence OF Africa
with South America and Australia &c form and III the
position Of the grand ranges OF upheaya was noticed
showing the three southern Continents TO be very
essentially alike. AL have lofty swels on each side,
with q. at depression between. In one respect
| Aiica and South America present marked differ.
eLcethe steiiy of portions OF the former, the fef-
iility Of the laei-wbch difference may doubtless be
the fact tina: Africa has its oii!est swell on
The asst cutting off the mist winds Of the ocean,
while tie cast swell Of South America may be
| conside,ed lofty table. Africa is literally shut
| up continent, hence its dIyness. Further con.
| parsons made between the contacnts ana
| their aIalogies exhibited, and IN conclusion
Iof. GuyOt announced as hxed principles that all
the continents due TO two systems Of upheeval;
the oiGereDoes in them, climate, productions, &c. to
results from those upheavals; iLeir grand general
character TO universal PLAN Their dlveisides to
secondary causes.
Prof JAMES HALL followed CON tie direction Of
Gent cyreIts Of depositlcn and the source Of ma
efials in the OCer PslcOZOic Rocks with remarks on
" the origin Of The Appalachian cham of mountains
1t il Observable that The LauIentian chain Of noun
sips north east 0. us have trend but slightly differ
ent from the direction Of the Appalachian chain. The
same must have been the di ecOE OF the great cur
rent IN Il. TO W. which formerly swept along that
portion OF tie earth surface which occupied by
the Eastern and Middle United States. The Apala-
clsn chain including the mountains from Gaspe Boy,
through New-Hampphlre and Vermont, until they die
out away at the South he cynceves 10 have been the
Jesuit of The deposits made by that current and this
conclusion ID baed upon or fortified by the observation
that The strata rs We ads nnco south westerly grow
thinner and die out. Tbus the Hudson River group,
TO- eco feet in thickness at Gaspe Bay, is badly 800
feet i'll the Mississippi Valley; the Devonian, 900
fee of Gaspe not half that III New.Iork, and less
than 200 ieet in the Mississippi Valley. This thinning
out of the strata he conccyes to be- owing to the ever
increased distance from the OF the materials.
We have, then, along this line coincidence with
ancient aud it, doubtless the case these
ranges Of mountains the effect Of its deposition Of
mat, ras, those ranges are no more upliited titan L.
the whole extent of the continent upon which they
sta1d True, We find strata folded and plicdted, but
they were before the upper SiuIian rocks shown
by their netanorpbi.ln but there is nothing III The
APPALACHIAN chain lower than the Potsdam sandstone.
He denies any special upheaval III these chains, be-
cause IN their elevation equal TO the thick
lees Of the original strata whence their materials
come; they Use IRON no Influence rising from below
through crack In the earth's crSst-they are but
deposits u,rcuo,c, uo. ann ,re.oo r.. s,,,.d Or
plicated without ele walton
Prof. HALL showed that az the deposits accumu-
lated to a great mass, the course under gravitaon
sunk and esary passng below the surface 1.-THE
sphere were compressed and thus folded AID pcated.
But his point was that the elevation OF the Apala-
chan chain is not 80 great as the thickness OF the org
ina strata, and that had the continent remained as
originally uphesved, had no current worn away the
materials IRON the taps, our mountains woud have
bee much higher
Prof DAsA considered it a remarkable fact that
l. If thickness aboud Indicate suDSldeDce
Of equal amount. The Gulf Stream is, in fact the
Atlantic Ocean pouring itself between England and
ireland, into the Arctic seas, returning along the
cuaets So the ancient current spoken Of by Prof.
Hall must have been like the present return Of the
Atlantic waters. Northern currents hug the coast and
determine its form. The old coast line, therefore,
must have been Labrador, and hence the cur
rent mutt have deposited it sediment along the line
| as described by Prof. Hall.
7. S. HUNT showed from chemical considerations
that the materials for the Appalachian chain may have
cone from Hrionan rocks now DO longer found on
the Lsurenuin chain, but which might formerly have
extended hither and been abIaded by the current.
A. c. RAMSAY showed by diagram how the sink
ing Of surface will press up portions folded and con-
toned, the tops of which beng cut of by abrasion
will exhibit the stlata exposed edgewise. In some
this cutting of will be extensive to reduce
a ountsinous country TO table-land.
Prof. LESLIE pictured that great current which
| formed the Appalachian chain rs sweeping across the
| low levels Of Asia ard Europe, which have since
emerged at some remote period, and striking along the
Labrador highlands cutting tnem away and bearing
the materials Of which they composed irto the
shallow SEAS and piGng them up to form new mount
| ain ranges. The views of Prof. Hall, he said. put
structural geology entirely basis, and If re-
ceived must give up fractural geology altogether;
that the two great fractures which the geology Of
the American continent has hitherto been basea must
give way to the idea u two great currents
| L. SIrRRY HUNT then described "some intueiye
rocks in the aisuict Of Montreal"
! Prof. LESLIE followed ION three comparative sec
tions VI the coal il Kentucky and in East
| "ern and Western Pennsylvania" Mr. LrsLIs said
that while note at this meeting such remarkable
advancing steps Of eur .cience the Identification
| the Laufentinp, Hurohian aud Slurian systems in