New-York tribune., 1877-09-01

u " srsnee o. the numerous vertebrate relh"nS ~ III
IL ,sraent decisive and IN favor OF the former view
.r,,s briugs up az important point IN Faieon'ooss'
- which my attention was drawn several years
one slv. the comparative value OF different groups
iu marking geological tune. ln examining tue
O =, ,,b ssfao care found shat for this purpose
-, a, their naturo Indicates, are most unsatisfactory
4.ses that n ertebrate animals are much pe''or
s that verieortes aford the most reliable e'ldeoe %
.o and other geological changes The suD-aiVE
s OF the latter group, moreover and IN l@e' an 'oi''
sotoai life are OF value in t6is respect hi""S -
- N the periecfion OF their organization Oh NOOr
-, -s,k FISHES. for example, are out shgn.y W
80 5v changes that would destroy kepVeS O' IDUs
-, .be higher Mammals saccumh under hnu0"0e' '"''
te lower forms pass through In safety Inc
.necatons Of thisg general la" ana i's '"-'' -
,r,u rtadly suggest themselves .
=, ~. l,w conclusive. that the hne II line there oe
r,ttn- oar Uretaecans from the Tertiary must ~
-. h. drawn where the Dinosaurs ana otler Meso'
p tsira,es disappear ami are replaced DJ the MAUI
mails. henceiorth the dominant type
s1orHs 1HAr WENT TO soUfH AMERICA.
,r,,reptlv asserted and very generally believed
a., tb large number of huge EdeHiaia when hveo IL
,-,t America during the P0st-Piocene, were INC io
-, ~ extensive migration from south America soon
s the elevation OF the Isthmus Of Panama, near 'ne
-, n tho Tertiary No conclusive proof OF sueh MI
80 has been offered and the evidence II -~e"s
. ca far ss we have It, Is directly OF
a IN his view. No und0ubted Tertiary Euen'~''S
have vet been discovered in South America Nn"o w
t al least two species our Mioceue ana curing 'uo
,o,,-or Of our lower POcene large individuals o. 'Hs
r were rot uncommon far nortn as the forty lAii"
Ii.l ~ latitu,le on both sides of the Rocky Noun
.; In view Of these facts and others Whlch sh"'i
Law before vou il seems natural u eonciaoo io
,,r present knowledge that the migration Wnich no
aoubt took place was frcm north to south ihe iueF
t,tes finding thus in South America cohgehAl hODi0
Aoarshed greatly for tme ana. although the larger
forms are now all extinct dmiuutive representatives %
The group stiu iuhabt the same region
ORIGIN OF HooFED ANNALS
Tho r-ngulates arc the most abundant Mammals IN the
Tertiarv and the most Important since they moi'ue
great variety Of types, some OF which we Gun uuoo
through their various changes down to the H'ene"
forms that eprcseut them today O' tue N'iD'0s
ions IN is comprehensive group the Perissouaet u
aI,ea rrr,lates are evdeny the Oldest ana through
, the Locene are the prevailing forms Although All
~ tl Perssodaetyles OF the earlier Tertiary are 0 VI
less seueralized they are still quite oi7tnct noi ~
.,+iodactycs even the base OF the Eocehe- one '
u, however, the CorgphodoatdG' which is wen repI0
tea at this horizon. both in America and Europe al
- essentially Perissodaeyis, possesses some enarac-
-, -bot ro,t 10 primitive Uugulate type from Wtch
t1e nresent orders have been evolved. Among these
characters are the dmiuutive brain which IN SIZE az"
-,ao1,o. p of the REPTILES. and also the five
D fooff
,nalian foot have been derived. OF this family ony
siole genus CorlgDh0don LBathmOdoB). is known, ou1
b were several distinct species. Tney were the a's-
-, mammals Of the lower Eocene, some exceeding III
size the existing Iaprs
In the middle Eocene West OF the Rocky Mountains
remarkable group OF neuates makes its appearance
Tbes animals nearly equalcd the elephant IN size but
had shorter limbs. The skull was armed win Two OF
three pairs OF horucores, and with enormous camhe
tusks The brain pTOportonaiy smaller thah III any
other Land mammal The feet had five toes
IN their general structure those o. Cogphodo thua IL
deatins some affinity with that genus These mammals
resemble in some respects the Perissodaetyles and in
others the Prob0scidians yet differ 80 widely from any
Known Ungulates recent fossil, that they must De
reoarded as forming 4 distinct order rhe Dfnocerdd
Pesidos these peculiar Mammals, which are extinct,
ana mainly OF interest TO the Biologist there were othefs
in the early Tertiary which remind us Of those at present.
living around us When a student IN Germany some
twelve wears ago, heard worldrenowned Professor OF
Zoology gravsy inform his pupils that the Horse was a
ft Of the Old World TO che New and was entirely IN
known p America until Introduced by the spanlards
After the lecture asaed him whether no earlier remaus
c horse had been found this Continent and was told
IN ry that the REPORTS 10 that effect too unsatls
factory 70 be presented facts in science This remark
led me- on NJ return 70 examine the subject myself and
ILave since unearthed with my hands not less than
thirty distinct species Of the horse tribe in the Tertiary
deposits o the West alone and II Is now, think, gener
ally admitted that America Is, after a the rue home OF
the Horse.
can offer you no better Illustration than this of the ad-
vance vertebrate paiaontoogy has made during the as
decade or important contributions to this progress
which our Rocky Mountain region has supplied.
The oldest representative OF the horse, at present
known, is the dimluutvc E0hippUS from the lower
Eocone Several species have been found, all about the
size OF fox Like most Of the early mammals taeso Un-
guatos Lad forty-iour teeth, the moars with short
Tie ulna and the hbula entire and distinct. and
there were four well developed aud rudiment OF
another on anG three toes behind In the
structure Of the feet aud IN the teeth the Eohtpps
indicates unmstalby that the direct ancestral line e.
the modern horse has already separated from the other
Perssodactyles In the next higher division OF the
EOcene another genus lOrchiPpus) makes its appear
ance, replacing Eohippns, and showing greater al
though stll distant resemblance o the Equine type.
The rudmentary first digit OF the fore foot has dsap
peared, and the last premoaT has gone over to the
moar series OrOhipDWs was but little larger than
E0hippuS, and IN most other respects very similar.
Several species have been found in the horizon
with Dinocsras and other lived during the upper
Eocenc with DtriaeodoH. but later
Near The base OF the Moceuc, I'm the BrOntoheriUm
beds 1nd thiri closely allied genus. Hes0hiPpts
which is about large sheep, aud stage
the horse There only three toe and rudmentary
spln bone the fore feet and three toes behind Two
o. the premoar teeth quite like the moars The
uina longer distinct the hbula entire and other
Characters show clearly that the transition is advancing.
II the upper Moceue HesohppWs not found, but in its
place fourth fo N0hPDus, continues the line. This
genus near the RchltbeTHs ~ Europe but presents
several important differences The three toes in each
foot nearly of size, and rudiment Of the
fifth metecarpal bone retained. All the known species
Of this genus larger than those OF McS0hppus and
none pass above ihe sIoeene.
The genus Proiohitpus OF the lower Piocene. is yet
more equine and OF the species equaled The in