New-York tribune., 1842-04-15
Mr.. Lyelrs Eighth Lecture on Geology.
povLnERs AND lcrBERGs.
Reported Tor The Tribune,

wla, we term the B0Hlder Formations or sorlc-
times the Norfolk Drift. The term boulder aP-
piled TO any large mass found resting upon the
superficial gravel brought from distance. BY
some, chiefly the writers of the last forty years.
this formation is called diluya; because they be-
lieve that this superficial gravel, and sand, ;.nd
mud, in which are found these rounded fragments
Of rock, have been brought thither by rush OF
some mighty dcluge. either Il; time at dit
ferent periods Blu, those who have thought tnai
they refer large par OF this to
other causes a:eic: the term Dryf-as not choos-
ing TO commit themselves ,e any particulars theory
exccp, that which i, certainly known 10 be true
that tlesc boulder, have been 1rijted. b. some
means or other, 70 considerable distance from
the patcn, rocks. from which, as fragments. they
have been torn You have so many example. in
this country. of these foreign rocks scattcrad
through bed, Of sand and mad thai il 5 not
=ccssary for me to enter upon the description OF
any particular localities in Europe II you pass
~ the great excavations that have been made for
streets IN Brooklyn, yon may see some forty or
mir! eetin thickness of what we cali rubbish,
unsnatlleh, confused mass Of clay and sand con-
OF rock Of various klnuS.= ] IFS
nay be near the Navy Yard, and in oil part.
OF the suburbs Of the city. The same kind Of for
nation may be seen in various parts of the North
OF Europe, ns well in different districts of this
Continent. In Europe it is particularly notice
able in the country bordering the Baltic begin
ningwith Finland and through part &c Russia and
Poland, to Pomeranu, Prussia, and Denmark,
through the lower part OF Sweden. The whole
country consists of land at 4 moderate elevation,
covered, 10 depths that have never been pierced.
with this boulder formation. sometimes thousand
feet thick. and often, indeed, still moro. 1t con-
talns no strata; and you would become sensible,
AFTER having made q geological survey. how very
rare are unstratiticd rocks which are not crystal
iinr like granite. Sometimes We find the boulder
formation. entirely unStraticd, passing into auo-
Their strata which is arranged in layers. The alb
>ence OF tossils-ot organic rcmains-is another
characteristic which makes ii difficult TO decide
the nature or origin of this neutrality-suspicious.
1t be tresh-watcr, formed in lakes or a marine for
faation formed in the sca-is a matter OF great
doubt from the absence of all organic remains.
Sometimes, indeed, we have found she'll, and
bones washed out OF tlle older rocks for, rcla-
lively speaking, this is = modern depositc-bcing
strcwcd over other strata containing fragments Of
them all, and occasionally of their mbcdGcI1 fos-
stratitcd and nnstfutiiica rocks
In tracing along this remarkable dcposi,c
through the borders OF the Baltic, we sometimes
find fragments of rock which must have Travelled
hundreds OF miles from their point Of DEPARTURE
and, as a general thing, we shall find that they
grow larger in size appronrh tho region
from which they were derived. This | foGpd TO
be the fact in going north from the margin OF the
Kline to Hol,tcin, and Denmark, where iound
fragments o! Scandinavian rocks in Sweden nine
ard sometimes forty feet in diameter; and ut last
the whole country WAS made up OF these rocks.
thus by tracing tie st;cam along, wc shall Ind
that as it d;minshes in size lie stones continually
diminish in their individual dimensions His
may be seen any where between the Thames and
The Tine, and by following it out in any region YOU
will become convinced that there hua been gon-
eral drift from the north. You may travel COR
eight nluc hundred miles over The plains of Rus
STA end you will find these E1raiics. as they are
called, associated to such extent with the rocks
IN the ncisNborhood, or immediately subiaccnt
that they have acquired the caor and meteorological
character Of the rocks of each country. IF, io,
example YOU trace The boularrs to the red sand
stone Of New Jersey, YOU will find them red. So
al Brook!yn, you will End that in grcas part they
red. Yet hare in the red base you find scatter
ed fragments Of the trap Of the Palisades, huge
masses Of granite from the Highlands. and some
of the green scrpcntinc of H,holicn, all mixed
together, and yet the whole redeemed By thccolors
and marked By the character OF the at! joining
sandstone. Soin Europe. ,hc boulaers arr white
III the Chalk CT Scandinavia: black in tie carlo
riierous formation near Edinburgh, where the bilW-
minous shale Of the coal Formation enters largely
INTO their compostlon> Sometimes YOU find them
entirely angular as it they had suffered amy OF
that mechanical rubbing against adjoining rocks,
or against each other which has perfectly rounded
other masses equally large. Seine of lhcse#are 80
Large ,ha, it is difficult ,oimagne that any force OF
water, which Is the agent usually assigned could
be sGlhCie.t to i0lltllem over and over neccssa
ry. Take some Of the gneiss for instance the cdg
of some huge masses have boon cut of, so thai
the whole Is as perfectly rounded Us Any Of the
smaller pebbles. Oiientmcs. too. these 60
Souldcrs have been carried across scaS-as from
she Scandinavian rocks 10 the south side Of the
baltic. We have them too, perchcd upon the
jura peaks, having. evidently been carried IRON the
higher Alps over = valley fifty miles wide. and
deposited upon ns,ilcrous limestone rocks, which
have nothing III common with those of the Alps !
ms IL the kind OF appearance which has SO per-
picked Biologists, and TO explain which, shall be
ono purpose of this evenings lecture.
will first, however, alludc To one ether appear !
4nec which distinguishes the boulder forulntion-
when itrests upon hard rocks-rocks which are
capable Of taking and retaining a posE--rocEs
which have rot wasted away by disin;cgra,ion-
we lind, upon removing the sand Sc tho solid
rock below sometimes polished so as almost to
answer the purpose OF loo!iins-slass; ut other
times we find it scratched and rilsed with long
parallel stripes perfectly straight Tor hundreds OF
yards, and sometimes Tor quarter OF a pliie, o.
casionally deviating from being parallel 10 each
other, but still retaining the same general direc-
non from north to south or sometimes 90 or - |
degrees towards the west Of thar direction
This is evidently common characteristic Ut these
erra;cs and any theory advanced 10 explain
them must comprehend that appearance.