New-York tribune., 1878-05-04
ACADEMY OF SCIENCES.
ROCKS AND ROCKY MOUNTAIN LoCUsTs.

CHIEF sorRCE OF FERTILE soIL-oRIGIN OF
MoUNTAINs-How ANIMALS ARE DISTRIBUTED
THE CAREER OF THE ROCKY MOUNTAIN LOCUST
1FRoa STAFF CORRESPONDENT OF THE TNBUsE'l
WASHINGTON. April 29.-The list OF excel
lent essays delivered before the National Acadeny VI
Sciences has not been completed in the previous eer
OF tins scries will be by those when are mere
given in abstract The geological essays OF froiessois
Pumpely and lie Cone give in brief synopsis lair no
ton of the most generally accepted theories aS 10 '"o
formation of the earths surface-its ha fere regohs
and its mountain The essay OF PROFESSOR hey
on the Rocky Mountain locust shows tnat the haps anu
character of the insect well understood ana tha'
our Western farmers not likely 10 suher inuen '"
its lncursons for some years to come.
SOIL MADE IRON ROCKS.
Professor r Pumpelly's essay on the HeIatioh oi
Secular Rock DisintcgatOn TO LOcss and Df mas DSeh
mentioned by title in nm earlier letter Many points OF
popular interest were presented in this essay Loess Is
caIcareous loan which vast areas OF the ears
surface in Northern China several hundred thousand
square miles In the rest OF Asia, yet larger arcas In
the Mississippi Valley perhaps an equal extent The
depth OF this formation In Europe and Amer
ica varies from n few feet TO 100 or 200.
While 1t can be crushed in tie hand TO mere
powder il often supports itself for many years
in vertical cliffs 200 feet high On close examination
IS found filed with tubular pores branching downward
like rootlcts these lined with carbonate Of lime
and give its consistency, owing TO which II breaks IN
a vertical plane, leaving always perpendicular walls
It's fossils are always Of land animals; chiefly
Of land snails. Richthofens theory Of the for
nation Of loess il as follows: When winds
in the interior Of a continent drained Of their
mOstuc-as for instance by its condensation on noun
ins near the coas-thc interior country becomes arid,
its surface is barred. and the products OF disntegraon
as the surface wears blown about by the wind and
washed by occasional rains from the hs to the valleys.
This material e however, nutntive to the grasses Of
the steppc; they grow in and are eventually over
whclmcd beneath it in their successive growths. Tie
Ioess thus burying its own products, becomes most
fer soil; the grain regions Of China have been under
cultivation for 900 years. without losing their produc-
tive power. This is partly due to its capacity for alb
s0rbng carbOnic acid and ammonia, but chiefly to the
capillary powers of its tubular structure, by which the
nutritive salts below are raised toward the surface
whenever there is sufficient moisture 10 I'll thcm or TO
communicate with the saline water below the drainage
level.
The weak point in this theory that the disinteGra-
ton IS not sufficiently accounted for, to cXplnn the
formation Of such vast quantities of oess. Professor
Pumpcly proposes TO add to the sources OF this material
ul the silt OF rivers after those streams are dry the
material they have brought down ia blown about and
becomes locss. (2) A secular dIsntegratOn OF rocks
has been going OH from earlier geological whcr
ever land has remained water for long periods
and this H. Of course more especially the ease with the
interior Of present continents This decay has been
estimated in general at depth OF 100 feet throughout
the Southeastern states; numerous instances OF 1t were
cited and its processes described by Professor Pun
pcy In the Northern part Of country this decaycd
rock was largely carried down by glacial action and
deposited rs morainc-ihe glacial TIL" The process
rockdccay would be most active In the lower levels
and hence these would form the areas most favorable
for the production OF lOess In after ages when tnose
levels were longer waiercd. Through such series
of changes MS are thus briefly skcchod the great basins
NJ
ard thus followed; those OF Northern Europe and
America were cmpticd by the ice OF the glacial period
but the preparation IN both instances had taken place
ages before.
THE STRUCTURE AND ORIGIN or MOUNTAINS.
An essay with the above tide read by the sccre
tary In the absence OF It's author Professor Joseph lie
Contc The paper is 10 considerable extent contro-
versia 1t Is intended reply TO objections that have
been brought against the "contrac,iOnal theory"
which explains the formation OF mountain chains by
being forced up by horizontal pressure, during
contracting process Of the cnrths crust The follow
ing general statement il made respecting mountain
ranges; they may be conveniently divided in two
general classes which. however, graduate completely
lufO each other viz, those which are composed or
single anclina fold and those when are CONFUSED OF
either Opcn IN the Jura or closely appesedas III he
ers The one kind IA formed where The earth Is more
ild; the other where yields more rcaih 10 the nor
izonta pressure hon nnus ARE p,s"' nv ,'tig'
somciiincs BY volcanic oubursts, and always by Gro
sion The various positions which the stratl may be
placed in. rather forced into by the above
proccsses, are clahorately set forth 10 the, es-
stances The objections which have been brought, on
various grounds against tho hyp0ihesls are separately
con .dercd aud discussed Finally Professor lie Cone
sums up his theory TO this effect: The place OF noun,
tain range before II yet formed, was n marginal
sca bottoin receiving abundant sediment from cont-
mental erosion line OF CshOrc sediments thus formed
gnrous softening both OF the sediments and Of
tie original crust on which they were laid. This
woud determine line Of weakness and OF yielding
IN borizonal pressure and therefore, Of the formation
Of mountain range, which would immediately there
after begin TO be sculpured by the active agents OF
erosion There thus three stages In the history OF
mountain: First preparatory stage oil standardization
stage OF Welding TO horizontal pressure which Is
period OF brtn aud growth thrc stage OF eIoslye
dcgradatiOn which period of decay, and gradually
into fourth stage OF mountain death and fossz
THE DISTRIBUTION or ANIMALS.
Professor Theodore GIN delivered an essay on The
Primary Zo0gtaphca Divisions Of the Globe, aud their
Relations" This largely discussion OF two recent
works "Aen's Geographical Distribution Of Animals
and n previous work Of II, arly similar title by Wallace
There are marked discrepancies between these writer's
and also among others who have considered the subject
The following divisions have been proposed for the ami
NAL Kingdom Arctic, North American European, In
diam African, Lemurian, South American, Australian
and Poyncsian. Perhaps Antarctic might be added
different writcrs have accepted some of these groups
and rejected others. aud no system Is yet agreed upon
Wessrs Wallace and Allen favor the distribution OF mann
mnis as n basis; Professor Gin thinks that the prey
aence all forms Of animal life sh0nd be considered
n we were 10 take birds alone should get very nearly
the present divisions OF our continents. II
we phould take fishes ms basis, division
II question whether the Arctic realm should be
maintained ns n separate division. III we consider the
land animals alone We shall lind no complete drTen-
tiotIon for the Arctic region II has no distinct animals
The European and North American regions are well dis
tingushcd the mammals are III very many instances
distinct and the fishes present half dozen families
ncculiar 10 each realm and similar division must be
conceded 10 Invertebrates. Professor Gil Is inclined 10
think the Arctic division might bc merged In the North
American. Possibly the Indian aud African might be
combined in one realm; together they would make a
great division OF the globe but unquestl0naby there
are iInuOrtaut minor differences between them. There
M rnn, Or vet grenler lIrcncc of Onminn ahHmt the