Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1898-10-22
wear. although they must exist without

I!f-'Nts
years. And we accordingl! arrive at the
conclusion that the larger desert tracts
must not only have existed as land Tor
an incalculable period, but also as desert.
Hence we can readily understand why the
animals Of Algeria and the rest OF North
ern Africa differ for the most part from
those of that portion OF tho Continent
living to the south OF the northern tropic'
the Sahara having for ages acted as an
impassable barrier TO most II not all.
But IL other evidences were requisite,
there is another reason which would alone
compel us to regard deserts as areas OF
great antiquity. The habitable parts OF
all deserts-and IL is difficult for the IN
experienced to realize what barren tracts
will suffice for the maintenance or ami
NAL life-are the dwellingplaces OF many
animals. whose color has become spe-
cially modified to the neecs of their en-
yironment. And II Will be quite obvious
that such notifications Of color, espe-
cially when they occur In animals be-
longing to many widely sundered groups,
cannot have taken place suddenly, but
must have been due 20 very gradual
changes as the particular species adapted
itself more and more completely 10
desert existence.
Among such animals may be mentioned
the beautiful little rodents, respectively
known as jerboas ana gerbils, together
with various birds. such as SAND grouse
the cream colored courser, the desert
lark. desert finches, and desert chat; ana
also various small snakes and lizards,
among the latter beng the common
skink. Although some OF the birds re-
tain the black wing qulls OF their aiies,
I'm all these creatures the general tone Oh
celebration is extremely pale; browns
fawns. russets, olives, grays, with more
or less black and pink, Icing the preooni'-
nant tones Very significant among these
are the desert tinches. which belong 10
the brightly -colored group Of rose fnches,
one Of these specially modified species
ranging from the Canaies through the
sahara and Egypt to the PunJab, WINE
the second is an inhabiant Of the Mon
golian desert.
Among larger animals a considerable
number of the gazelles are desert dwell
ers. and lions are likewise 10 a great ex-
tent inhabitants of desrts-as, indeed
is true of tawny and pale-colored animals
in general.
All the animals above mentioned be-
long however, to widespread groups,
which are common to the desert tracts
Of both Asia and Africa, and they do not
therefore, serve TO prove the antiquity
of any particular desert, as they or thelr
ancestors might have migrated, and pro-
badly did migrate, from one deserI 10
another. Birds Of such groups are, ol
course. even more Intrustworthy than
mammals, owing to their power OF night
And among those referred TO, some, such
as the sand grouse, can scarcely claim
IN he regarded as exclusively desert pros
since they are partial 10 any open' sandy
plains. like those Of tAe PunJab, or even
Norfolk. ..
The case is, however, very different
with certain Of the lager mammals, as
notable Instances being afforded by the
antelopes allied 20 the South African
gemsbock. All the members OF THIS group
are inhabitants Of mre or less sahuy'
open districts, and noie range eastwarus
OF Arabia, or possibly Bushire. me
en-, hook itself. together with the beisa
of Eastern and Northeastern AREA are
Inhabitants of districts which do not, for
,he most mart come under the designation
az tvpical deserts And We accordingly
find that they are by 10 means very pale
colored animals, while both are remark
able for the bold bands Of sable ornament
ing their faces and limbs. on the borders
of the Sahara there occurs, however
very different member OF the group
the white oryx-differng from all the
others by It's curving horns, and likewise
by the extreme psllor OF its colorauon'
which "a mostly dirty white, with pale
chestnut on the neck and under-parts.
Obviously this species las been specially
modified as regards colpation for the eX-
igencies Of a purely degrt existence, ana
as il is also structuraly very different
from all its existing lndred, 1t must
clearly be looked uIon as very
ancient type, which commenced It's
adaptation to the surroundings OF the
Sahara ages and ages ago. The Ara
bian desert Is the home Cf another species
Of oryx. which, although more nearly al
lied to the East African beisa, is a much
smaller and a much pahr colored crea-
ture. In this case aAo there would
seem little doubt that TIE period when
this animal first took TO a purely desert
existence must have beel extremely re-
mote.
But an even more stirling instance Is
afforded by another antelope remotely
connected with the gemhOck. which -
an inhabitant OF the Sahara and the Ara
bian desert, and is commonly known as
the addax 1t is an is,lated creature,
with 10 near relation n The wide world,
easily 10 be recognized by its dirty white
color. shaggy, white name, and long
twisted horns. 1t must have branched
off at a very remote epoch from the gems
mock stock, and affords almost conclu-
siye evidence of the antiquity Of the de-
serts it inhabits since we have no evil
dence of the occurrences OF allied ex-
tinct species OF other Countries.
Some degree OF cautiOnis, however. ne
cessary I'm drawing Condusions that all
isolated desert animals hive been evolved
in the precise district they nov inhabit
A case in point is AFFORDED by the saiga,
a pale-colored antelope without any very
near kindred. inhabiting the steppes Of
Eastern Russia and certain parts Of 81
IBERIA, where 1t is accompanied ~ the
hopping Kirkhiz jerboa. Now, since fos-
SLICED remains of both these very pecu-
liar animals have been discovered in the
superficial deposits Of he southeastern
counties in England, it IL a fair inference
that physical conditions similar 10 those
OF the steppes (Which. By no means are
true deserts) obtained in that part Of our
own country at an earlier epoch Of its
history. From their comparatively iso-
lated position in the geological system,
as well as from their occurrence in the
strata referred 10. both these desert ami.
mails evidently indicate very ancient
types, and they accordingly serve TO show
not only that the semLdesert sreppe area
formerly had a mucl greater western
extension than at present, but probably
also that the existing portion OF that
area dates from a very remote epoch.
Hence they confirm the idea OF the early
origin Of the present deserts OF the Old
World and their inha bilants.
IL will be gathered from the foregoing
that the deserts and steppes OF Africa