, 1866-07-08
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III, Geological Dii;.cao5verte.-1 i;.a5 -1,nmtgrs'
80 | 1t ( :

Ills ceo1o.lea1 mtEre-
;. Mon DtseorFaEed.i 7l!f- -
In May Professor, ,Agassixhtgrn & series Of
popular lectures In ';Rio Janeiro, onTthe-
:. <.Formntion oftheAmaxon Basin.' From:A
akateh published in the Anglo Dra-Q 1s"'ss
vo gather: the following, interesting summary
Of some Of his geological discovezIes IN b1aza:
"The mass Of the Amaxonic deposlts Is
found above the level Of the sca, faouSn ~
plane OF little elevation. The ioR3t oees
are seen everywhere, from tho Huat:aSa 70
Marn]o. They Mera torTsd 3ss. "'th ainags and m
everywhere they present triple cnatacset.
At he betiom arc marines, clayb so hne- 90
triturated that the grains are almost indts-
tfnFuishable and forming m absolutely ho-
INDIGENOUS and uniform mass Beneath these
Il tard coarser and coarser. Thus there
are: first, coarse sand mixed With rounded
stones second. fpc sand deposited IN fcSu-
Iar and delicate beds third, banks Of cay 50
fine that they are at times as fne tSSa a. spESe
q psps5 Ihis !. the .orae5 oTde5 e1
q ssnch a nnifnrm deposit Of thiu beds Of
excessively lrltuFated material. without
Tnixtnre at rolled stoucs, and without inter
nal modification could only nave Nn,;naross nsen a.,
nsa@, no.,,ed tssn! na1s5s IT t IS ioaoa idsnte;l
cycryTbrrc, aud also IN the valleys OF the
1otc;;si r;vers. The Tocantins, Xingn. TnpaJos,
Purus. Ice, Japura, ard the Rio Negro. In
which last the Professor observed 1t up to
the junction with the Rio Branco.
siore Eiill, these same clays appear in the
valley ofthc Marauhoa, ut ltap!cutn, and IN
that ofthc Pagnnhyba, possessing The same
characters and the same level.
..Tle bed which terminates the deposit and
forms its surace IL q kind Of yArnIsh, OF a
uniformly smooth crust, without cru.iou,
t3.nf tf,N rfN = 1hnNHr6
aftcE tue formation OF tho bod
"T1o believes there existed, prtmitiye]y on
the plain glacier Of most enormous Size,
which resting on the side Of the Andes, ,slopcti
toward the ocean and formed Will tts loWess
extremity, a toleaably. elevated moralnc.
From the mel inE Of this glacier resulted o
lake, whose waters rose TO the level Of tue
sandstone. The dyke, eaten AMY, ,e1cayated
and threatened, yielded at last, and the W.
tcrs rushed with f1rio,1s impetus n the dlrcc-
surfacc OF the plain, and cutting n~av the
urpcr santlstanc ,lpcqun1ly. Alterward, un-
der quiet waters, the deposit Of tho upper
tFrom the level formation Of this basin,
4hc diversity OF The Amazon from, other great
rivers arise. The principal strca ms havc nc
clearly described basins. There u not . AIN
c1e capal; there Il q network Of chnnnelB,t the
moro complicated tue more Important t!it
tributary. The anastomosrs bstwecn tht
n1HCttHt fIfCAtHA AFS cALIEu1CA} HcluEAl
Titus tic Mndetm sends au arm to the cast
which. uttcr receiving various inferior
branches Joins the elIcf artoFy onlT at WILL
lIells. Ti,is chlef arscry, in its turn, Is like
wise nt times almost iudlstinGnlslsa1lc, mud u
Is unknown whether these multiple anastn
nc:cs Hre, ~ not. ancient beds abandoned b.
tlr Aulkzun. .....
HThcsc nrnAt o1noscs do not exist solely j
the proximity Of tho tributarios; !he Boil
mncs Jutns tho Madeira hnl Tho Amazon
further III the Jarurn extends ranlt1catlon
rcAclng eyrn TO the lilo Negro. S0tlc Atnn
Eou set,la waller ~ it, own tributaries, to b
af1elw ward rerrlrod through thc.a agalti.
"'fho cht1rtitslona Of tho Kcnaoxlsl We,
thsn In brlct: d basin elevated Il, n etrla1
extrut nbDvo tAe oceau, slightly Inclined 1
wnrd tho sen. In which dtpDsIts Hrre prcclt
.tatcd In pnIalIci hedl, at evident index
tic tranquility ttof The WatcrA{ q baalu cot
plutely closed In, a ltasin, nnnaly. oxsendtt
in other tunes much beyond Its present lit
til. This last potnt IL demonstrated by Il
Identical nature ol Tho claYs md the nan
atoucs found on the margin ot thd valiuya
tha Msrauhno tat 1taplcuru} ind the FL
nhhybA.
Tie DYKE which clossl Ia The Amazot,
basln cot,rychcndsa ID lis precincts tic VI
1cys oi tllrsu two last rivera, ct rather, Il
vAlIcY Of the Amazon did not terminate L
tween Macapa aud MhrAn1,no. To form
i1ra OF tis snrfacc II Is necessary 10 trlcntal
ptolopE This rallcy, and tlln continent ttso
- much NJ IL ilrCdch 10 Tttidcr the ftnplcii
aid Tho l'atuahyba tributaries IT The Asna1
.-'hnt IL, IT lca,l o,r hundred traguos TIC
III tlu rnst,a