New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1875-08-16

occur tho prssilutan rocks Of Madoc- the EoSoo"
Basarcwm u Gumbei and the Cocoon Cdnadense, nrst
made known ~ Logan. In the Laurcntian OF CANADA.
The first Of these represents creature mat may
| have been a melIusk allied tn Pates ~ Some obscure
form Of cru stacoau Tho cylindrical holes called worm
| burrows, are of quite uncertain In their
1 reference. They may represent marine worms
| IN no respect different from those now svariIi-
| ing on our shores. spOnges, o. corals. or
senweeds In any case they afford little help IN explain
ing the teemng lie OF the prmordal seas and
only hope that the vast Thickness OF sediments which
Tile in the future One slender light in the dark
it, however. afforded by the E0so'n t5orTicnn'
neced with tho stiff older Of thu Lsurcntian It
therefore points backward to what 10 rs the dawn OF
ing fauna on tie other hand Aspidefia and Seo0.iS
may G ne y es S B BSs perod Of
ton from the ProOzoa Of the I@ureDtan to the higher
marine life that succcedsa Passage to be more fully ex
painc perhaps and it's great gaps filled by future dis
coverles bat winch may as ~ some i.f ptrou s W.
complicated with contenporaneous transition from
shaowwater conditions in the localities open
! ~ EXPLORATION ,,
nature IL reject this stand face TO face
VITA Tie ar" paid mystery Of tho abrupt manifestation
OF the PrpOal fauna without even SO n'ich OF prep
arston may be supposed to arise from Ia" previous
How then stands the question as the Proto oranifer
In answering this question, we shond think endeayor
weight probabilities and anaoGes which may ia
way another sway our opinion
| LAURENTIAN ROCKS OF ORGANIC ORIGIN.
First We inu u prepared to find that those old Nys
alline rocks which call Laurean, have real afn
icy with intrusive GRANTEES an other gncos masscs hut
ase most nearly allied to modern ssinentary deposits.
That tte original cienicl character ~ SOHO OF these
ancient sediments may have differed to extent from
that Of more modern sediments do not doult
Yet it is true that the common Of them, rs the
Gnei,ses Diartee and Mcaschiss. conssOf precisely
the same clements which appear IN modern cays
and sand: and that where Local alteration ha1 affected
more modern rocks, these passing by insensibe
gradatons into similar mctamorlhiic Sod- Further.
when old crystalline rocks sbicsted to subacra
disntegratien they resolve themselves again into tho
most common scdmcutiry materials.
Anoth cOnsdsrs ton hcSe il tho unequal manner in
which sediments become altered according TO their com
position and to the extent which they perneabe
b heated waters and vapOrs For this reason also Don
tglious beds OF rock will often H. 10 differ
nnch the degree of their alteration. Further some
beds and especially mc5tones. continue 10 retain
traces OF organic structure long after these hayo per
-hed nesbborins beds of different chemical com
position More especially when In lines tone the cavi,cs
snd pores the fossils have been penetrated with other
mineral n,ttor. IL would appear that nothing short 81
actual fusion viii 10 olitosute them. Again, 1ni-
soscopc structures odcu vol preserved when TIM
external forms have been lost, completely Insep
arabic Fl rom tine matrx, and in the present state OF mi
crOScopc there Is little danger that IN such seci
any experienced mcroscopst will fail to perceive
tho difference between organic and crystalline structure.
Having freed ourselves from misconceptions of These
kinds may next turn to certain Prescriptions estsb-
sicd ~ the constitution % the Laurentiin rocks, and
the minerals contsincd III them.
The lme,tones az TIE Lsurcntis1 system 81 g4sS,t
ticiResss and vast geographical extent. Sir w "a
Logan has traced and measured 1hIcc principal bands Ok
these limestoncs ranging in thickness from GO 20 lSOO
ica and traceablo continuously in district Of Canada
for than 100 miles, whio their actnal horizontal
must be Enormously groatH than this dis
lance would indicate. These limestoncs
also associated with Gneisoso and Schstosc
bed.. exactly in the way in which
Paieozic iIuc~ones associated with sandsones and
shales; and SONS Of the ordinary limcstoes whlo
othOls less dOiomitic. IN which also they
ir-cInlie tia PliroLoc limcstOnes. Eyory geeloGi'
lows that Tx hud which tho succeeding geological
uOri0ds the represent Ives Of these Lauren .le-
Ou fsilcrOui. bat lcre lY composed n
the debris of oceanic org nisn.s aud that is is 10 the
Ircr anu ,ay sal!inc beds that as statement most
fully apples May we not reasonably inftr tiab tho great
Laurel! ism lir.,siOnes arr OF similar orignl
One feature af those beds which has sometimes re
c,Iycd yty different ntorpr cation would here lacs
siiica,cs and especially of serpcniiAe ana Toanta
with the Dmos0brs, assocfsiio not uniVorsil but 10y
be affirmed to throughout the whole serie Of
a,uine "rssnG a,nf e, p Ia anG cngfS iOIas'.i
trGc tdat H. Siiicn ornd la different formations differ
somewhat in composition hut Dr. otefry Hunt ba shawn
Sat me SIP'hun'H ion', ioS'ifc, ali iAo various
Glnnc"h$ consiitHta single se'i.-. whose no'nbo:s
coitrs are not essentially distinct fo, the mort enccnt
| ocyprntiue.
pac" from The facility aho led Tor tic combination 0f
silica with btse' arising from TIE "Scn0t " organic
matter in The bot, An. and secondly irn the abund
Of scn'lc 5sca In tho har Nai@ of datons. kaho
laraiit l sIhstA ~llr t"aa I'rin mo ch"f bo'h %
! animals building Ihrr skeletons Of rGriOnaie 0f
Inn. andIor ,encenly having need OF silica. In tAs
coiroIitia in'tlr, rejected by iorainnifcn and
o,hcr hdn''c marine animals having cacarcQI, skrc
tons. hod thcIaotr, mat tho .ssociaon OF Sefcntno
ana ogante VITA Tie La'r"n.iNn linrst"ncs ahuid, an
additional Tsi,on for Regarding thHn orGaur. whc il
also cAa'in, thr favorable condition. IN which orsiti-
acii exists for The pofnanei fi- alton oi tio strife
turcs Of tle-r t'Sts.
Iut again trc ave vlst quantities of carbon these
lle-pnc0 and t!u associated brd>. TIE quantity Of
bo 10 ''he lh,se ioS;pl, ~ iha io"or l1nftasu III
tansl' IA a. iiyc esrfsic shown GGisiaiabl' Via
hai IN similar tbckcsst Of tho carbonifc ron. system
Bul what groosisi refers tho carbon @" Che paec.oc
rock, to any ohrr than organic o'isiut Irn9 II I,
This carbon of the Lsufcnt-n is in To s.rte 81
dics similar material in other niiood orks t,r exam
pie. to Tao graphite ,haes Of the Sl1n ~ Eastern Can
ada and 10 The ct"l ri khouc Island.
Lastly ouSht we not Z" alt @rh some yau: 10 that gen
o. .9i =, o,,, ~ Dr. LINZ 1d T AM ~ nat
rozido Of iron ms been organic mater IN tss case what
iucn.iable quantities %: pcriahrd car5p os master
mast be represented by the great bells OF mdnette Ia
tio Lamontian.
FOSSiLS ~ LAURENTIAN ROCKS.
st. tnon IL is not unreasonable 10 believe that the lau
rciiau m,s'oncs may be ~ organic origin the noSt
question ai Ieaics tao .ao OF preservation in
which mo Ietia such suppo,ed Organisms may
1t would no conceivable that tina process Of crystalline
guncut of particles migl svc proceeded far
entirely obliiorate all raes Of organic form strHc
tre Judging from oJh,F oascb Of aN,fcl hestJcs, tnt
would no scarcely likely In such HnesOne it is trc,
tho fossils often obscure to make little appear
Il fresh fracture u the stone. bul thoy may pro
sst tlD nsclycs distinctly the weather srra0os, In
consequence difference oithet ia resisting pOSeS
x hardness between tho fossil md tina ma,iS. In
c4e. also lhcy readily he dsv tpi ~ tho scion ~
All acid and s fTclscitly their microscopic tex
wi,Ii the eXlI1l. forms entirely
cnnlcd There lew crystllii.e marblo. fossi,
if.ioHs that do Oi OK1t indictIsOns " taies true
t.ife IN Other Of thceO ways.
was precisely in tho sisOvo indicated that
Cat,elS lir brought 10 light. The sts Of
it, iattencd cisn'es6 ts with Serpon'ne iOg,up- or
thrrrI of M,