Review of Recent Geological Literature. <>7 
mark upon the article. On one point alone we will venture to express 
dissent. Writing of the ancestry of the horse he says : 
"Considering that a parallel series of generically identical or closely 
allied forms occurs in the Tertiaries of both Europe and North America, 
it has been suggested in both continents a parallel development of the 
same genera has simultaneously taken place, that is that in both regions 
AncMtherium has given rise to Hipparion, and Hippa/rion or an allied 
form to Equus. Now seeing that it is evident that in the ease of species 
of a single genus the evolution has taken place in separate lines, that is 
to say, that the existing Indian species of Cant* are probably derived 
from the Pliocene forms of the same region and the Brazilian species 
of that genus have their predecessors of the Cave-epoch of that coun- 
try, there appears no logical reason for refusing to admit an analogous 
parellel evolution in the case of genera, and there is, accordingly, a con- 
siderable probability that the hypothesis may be true. Prof. Cope con- 
siders that in one country ProtoMppus and in the other Hippa/rion was 
the immediate ancestor of Eqwus." 
In regard to this we may be allowed to remark that if we understand 
the hypothesis aright there is a very wide difference between the two 
cases. While all the CanidOB of one country may have been derived 
from the Tertiary Canidce of the same region we do not know any case 
in which this process has resulted in the production of an identical 
species in two places. It seems scarcely credible that conditions should 
in two distant areas be so closely alike as to yield the same outcome. 
The admission of this position consequently does not lend any support 
to the other. That two distinct lines of descent through distinct 
genera should end in producing a single and intensely specialized species 
on the two continents is to our mind in the highest degree improbable. 
Moreover, when we consider that communication has been repeatedly 
opened between the continents during the Tertiary era it is not neces- 
sary to maintain a hypothesis that makes so great a demand on faith. 
It seems a more probable view that after reaching a certain stage of 
^development on both continents the race was cutoff on one and then 
reintroduced from the other. 
A few pages only are devoted to the Rodentia which excepting Cas- 
toroides, are chiefly small. The Carnivora are well treated in :i:> pages. 
The Insectivora and Cheiroptera follow, and the author then reaches 
the primates. It is not a little curious to note that this — the order to 
which man belongs — is of a date as early as any of the placental Mam- 
malia, several species of the platyrhine section occurring in the lower 
Eocene of North America and in the upper Eocene of Europe. The 
Catarhines, however, only appear in the Miocene while the Homintdce 
are. in the author's opinion, of Pleistocene or very late Pliocene date, 
lie considers, and with justice, that all evidence of an earlier dale for 
man is at least uncertain, if not improbable. 
I n conclusion it is refreshing to the classical polaeonotologist to see 
the author's efforts to reduce wherever possible the barbarisms which 
