The Daily times. [volume] (Richmond, Va.) 1886-1889, 1889-04-24
FORMATION OF ISLANDS,
THEIR CREATION DUE TO VOLCANIC
ERUPTlONS AND OTHER CAUSES.

eRUPTlONS AND OTHER CAUSES.
scientific Information Not Given In the
Biographies Islands which Have iicen
Blown Up from the Oceans nottom.
Detached Pieces Of Land.
Your ordinary text book u geography,
'as She is written" talks barely and BADLY
a'out the size az counties their boundaries.
thyir rivers and lakes capcs and head lands,
their populations their religions and their
chief producis These are an facts. no
doubt. hut thcy are facts which resemble
pearls destitute Of any string whereby they
may b. converted into necklace and thus
mado useful and ornamental both Nv be
ncf therefore leads 20 the assertion that we
shopld become more scicntihc-but not there
bv l.,. popular-in our geographical teach
in.. boz schools and This very subject Of island.
shows the way Of reform Science, ia thi,
sense. dives below the bare facts of the text
bpnhs and seks Co give reasons for these
FACTS 20 places itself in the position Of am
-xp1ltor auI cXpouuder Of the manner IN
which our world ani IFS affair." hasscomo to
assume their existing order
DUE TO VOLCANIC ACTION
Geon phicaily. an islands are regarded "a.
of mHcl the same constitution They are dc
iaehet masses of land surrounded 10y sea,
ami differing. t0 the mind Of the schoolboy
OF schoolgirl chiefly m size Australia is
big island. Madagascar is not so big ond
from Ceylon onward 20 Mauritins or the
Azores thoro are found an degrees and erada
tion- of magnitude This. with a tow details
about tine quarters of the world IN which
Islands exist. and with some ideas about pro.
ducts and peoples, complete the geographical
knowledge of the average man and woman
Science take, up the matter where common
place geography ends Dts story IL nsks, first
uf all. what islands really nres and how ONE
ISLAND differs from another As "a result Of DO
investigations. science soon discovers that
islands may he divided by their nature into
two distinct qfs or classes OF These two
divisions. the first includes islands which can
ny claim to That title from tho first day OF
uer existence. in that they have never
formed part and parcel Of any larger mass Of
land Thus we first distinguish tho So called
NffI"HAINAN ArtAtNAnr WtAtNtf tAh| ANt' tAf'fl''f
have been thrust up from the sen depths by
volcanic action. fo form detached masses Of
mni oxi-fine. Sc may he. many miles from "a
continent or mainland.
Then comes asoconi class Of islands which
are called "c0utmoufal,' because. whatever
their size, form OF situation, We can prove
them fo Boz ceolo-cal.y part and parcel of a
b.,.,r tract o. land They arc separated and
ii.iouei fragments. SD 60 speak, 81 q larger
.aud mass Under this hcad are tOho included
muv islands $500 know The British islands
aro simply detached parts Of the European
continent. iust as Trinidad is q fragment of
South America. or as the Malay archipelago
represents The broken up land which, once
upon ume m SIS bale and solid state, coz
nrciel Asia and Australia. Even New Zea-
land and Madagascar are continental islands
100 their way. although the exact dates Of
tueir separation may be very hard 10 trace in
lle ni-t- of geological time.
rHE uTrfarNcE SCIENTIFICALLY EXPLAINED
HAVING ihu- succeeded n distinguishing
aofncu islands which. like ST. Helena, the
Azores. tlo Galapagos and SD forth, represent
the eruption, into the earth outside mas of
volcanic matter. and those which, like Brit
ann. Trinidad and the West Indies, are really
tle detached p.eeosoi large land tracts, 30 Doe
hooye. us 60 inquire further into the history
of each group They are separated from
choir mamuuds, it may be, by abysses Of
ocean, on the other hand the continental
island. have. relatively shallow seas scpaat
n. Them from their nearest continents
Wiuo-s. to provo his statement, tine Ger
mau ocean. tho English channel, the sea Doe.
tween Trinidad and America or the genera
depth of tine seas around the Malayan ID
and- Wchni test not only of the nature
of am -laul m tine depth of tho seas around t
apart from iis rock structurc-but in th.
ca-e of the continental islands we can assure
our-elrc, of tho length of time they have
been separated from their mainIauds by hay
in. regard o. the samG matter of ocean deep
nes,
The Azores as volcanic islands. arc thu.
SEPARATED from Portugal by sea varying
IRON 81 oa1 to2101 iathoms Within "a short
distance from tine islands them,elves the sel
is about .OOJ lnfhoms deep, within 300 mile
90 u.s. 500 mtaom- and soon deepens To 300
Wuh the B.rmuia- the case is similar. SOME
$40 miles of we reach the sea bottom m
g.. s.5aud $50 fathoms 81 Helena has SEQ
of o. $3.50 fathoms deep between 10 and Africa
some lUJ miles off, Coutrariwi~e. the sea
around our own shores is comparatively sbal
low. but. as ) have remarked, whenever %
continental island shows like Madagascar,
deep channel between DO and Dos main land,
the story such depth Tells as Is one OF long de-
tachmcnt from the mother country.
rLANr AND ANIMAL LIFE
So far, Islands have shown us thatgoologic
ally their history IS interesting n respect of
the marked variation between the two classes
Not jas, interesting Is the additional evidence
about Islands which their animals and plants
bave 10 tcli Whence. let MS ask, have Gle
tached Islands like the Azores, obtained their
animals and pianist Upraised from the sea
Del. as have been these islands, their living
population must have been derived from
othc. and previously peopled lands This sup
n.>uon 30 confirmed boy our finding that on
tine Azores we discover no animals or plants
excluding those Of mans Introduction
which are not found on the Portuguese coast
Tie rabbits wcaseis, mice and a single kind
81 Nlqrd found iu the Azores are importa
lions
The birds which. Of course. can tly over the
Intervening sen. arc those OF Europe, such
also are the insects, and such, again, are The
plants. I'm q word. there is nothing about
The animals and plants of tho Azores Which
sc cannot explain by reference TO their Eu
rop.au origin Then also, on such detached
islands. we cannot expect 10 End native
1uadiupeds or frogs, Tor these animals Wiz
not face and brave long swim ia tie seq
.ua.DUrI. DO is precisely those animals al5