New-York tribune., 1877-09-01

During several visits TO that region, many facts we're
brought t. my knowledge which pnder t.is more thu.
probable. Nan this time savage, and was
doubtless by the great volcanic outbreaks TO con-
time migration. TINS at st to the south, since
mountain chains were barriers the cast AZ the na
tive Horses OF America all extinct, and Is the
early man did bring the Oh World animal with hiu
his mlraiions slow believe, moreover, tEat MS
slow progress towards civilization was IN no small de-
gree due "a this came carse. the abscucc OF the Horse
tits far from my intention 10 d 10 the many theories
etant in regard early civilizations in this country
aud then connections with the primitive inhabitants OF
the later Indians but two or three facts have lately come
to knowledge which think worth mentioning IN th
connection. On the Columbia River have found eVi-
donce OF the former existence Of Inhabitants much suDe
ror Indians present there and OF which no ira
dltion remains. Among many stone carvings which
saw there, number or heads which 30 strongly re-
senhe hose Of Apes that the likeness at once suggests
itself Whence these sculptures, and by whom were
made. Another fact that has Interested me very
much the strong resemblance between the skulls Oh the
typcal MoundbuIders OF the Mississippi Valley sud
those OF the Pueblo Indians. had long been familiar
with the former and whcu recently saw the lat'er IL
required the positive assurance OF friend VINO hao n'"
self collected them in New-Mexico 10 convince me tha'
they from the mounds. third iact ana 'e'e
Man TO the Archaeological whose province am even
now trenehing IT. large collection OF Aound-huiiderS
pottery over a thousand specimens, which nave re-
Gently examined with care found many pieces oi
elaborate workmanship nearly like the ancient "aler
lars from Peru that no one could iars doubt thai some
intercourse h@d taken place between Tie widely sep'ou
people that made them.
The oldest known rcmlins of Man this continent
differ in no important from the bones OF the
typical Ind an. although in some minor details they u
cate a much primitive race THESE early heniahS'
some OF which are true fossils, resemble much more
closely the corresponding parts OF the highest Od worm
APES than DO the latter Tertiary Pmates or even
the recent American Monkeys. Various living ana fossil
forms Of Old World Priuaes h up essentially Tie latter
zap. The lesser gap between the prifhiuFe han "i
America and he Anthropod Apes IS partially ciosen OJ
stI forms OF meI, and doubtless also oy hsh''
Apes. now extinct Analogy, and many iacS ~
, well, Indicate tnat tins gap was snaiier III tne
past Ii certainly is becoming wider nov with
every generation for the lowest races OF men
Will soon beeome extinct, IKE the Tasmanlans ana TIC
hig, 81 nes cannot long survive Hence the ntefme
diae forms OF the past any there were become OF s
greate importance For such missing links we must
look the and later Tertiary o. Africa, when
regard "A now the most promising field for exploration
in the Old world. America, even the Tropics can
promise no such inducements 70 ambitious explorers
We have however, equally important field II less At
tracye in the Crctaceous Mammals which must have
left their remains somewhere this continent In these
two directions. believe lie the most important future
discoveries IN Palgontology.
A. q FOR many changes OF structure In mammals
during the Terlry and Post Tertiary, regard, as the
most potent Natural Selection. IN the broad sense IN
which that term il now used by American eyolutonists
Under this head. 1 include merely a Malthusian
struggle for lie among the animals themselves, but the
egually important contest with the elements and ali
surrounding nature b. changes IN the environment
mgrations enforced slowly in some cases, rapidly IN
Others and with change OF locality must adapa-
don To new conditions extinction The life history Of
Tertiary mammals illustrates this principle at every
stage ana no other explanation meets the facts.
The real progress OF mammal life in America, from
the beginning Of se Tertiary the present. well Illus
,rated Dy the Braingrowth in which have the key 10
many other changes. Tae earliest known Tertiary mann
mails al had very small brains aud IN some forms this
organ Was propOrtonaely than in certain Reptiles
There was d gradual increase in the size Of the brain
during this period and it interesting TO nd that THIS
growth mgnly cOuiued - the cerebral mspheres
or higher portion OF the brain. In most groups Of mann
mails has gradually become more oonvglht'i,
and thus increased quality welt quantity. In
some also the ccrebeiHm and olfactOry obes the lower
parts the BRAIN have diminished IN IL Che
long struggle for existence during Tertiary time the bs
brains won then now; and the increasing power thus
gained rendered useless many structures inherited fron
primitive ancestors but longer adapted 10 new con
ditions.
Another of the interesting changes in mammals during
Tertiary time was in the teeth which gradually
modified with other parts OF the structure The pilml
tive tooth clearly cone, and all others are
derived this All classes OF yertebraes below nam
| ls
have cOnical teeth II any, simple modification of
this form The Edentates and Ceaeeans with teeth
tain tyre except the zeugodonts, which approach
the dentiton OF aquatic Carniyores. Ia the higher nam
mails the incsors and CANNES retain the eonical shape
and the premoars only in part been tranformed
The latter gradually change TO the more complicated
noar pattern, and hence not reduced moiars, but
transition forms from tue cone complex types.
Most of the early Tertiary mammals had forty flour
teeth in the oldest forms the premoars were ali nm
like the moars while the crowns short, covered
| with enamel and without cement Zach stage
OF progress in the differentiation Of the animal as
rule marked by change in thc teeth one Of the
most being the transfer, IN form at least OF
premolar TO the noar series and gradual eugthening
OF the crown Hence. IL is often easy to decide from
fragment OF Jaw to what horizon Of the Tertiary ii
belongs The fossil Horses OF this period. for example
gained grinding tooth for each toe they lost, one III
each epoch. In the smgleOed existing horses, all the
prcmOars like the molrs, and the process s ~ an
end OOther dental transformations OF equy Interest
but this illustration must suffice.
The changes IN the limbs and feet OF mammals
during the period were quite as marked The foot
OF the primitive mammal doubtless plantgrade and
certainly tiytoed Miny OF the early Tertiary forms
show this feature. which is still seen in some existing
forms This generalzed foot became modified by
gradual loss of the toes and increase In size OF the
central ones the reduction proceeding according 10
systematic methods, differing ia each group Cores
p0ndng changes took place IN TIE lind bones OhcFe
suit was a great increase h s7eelHss the power was
applied so rs 70 act only IN the plane Of Motion The
best effect Of this specialization Is seen TO-DAY in the
horse and Anteopc each representing distinct groupoi
UnguIates with five-tocd ancestors
II the history of American Mammals as have briehl
skeched H. seems a whole incom plee, and unsatisfac-
tory We mu. remember that the genealogical tree ofthis
class has its trunk larger limbs concealed beneath
rf.f