1872.] 5D [Perry. 
which he terms Terrace or Recent, to stand in correspondence with 
the Post-Pliocene and Kecent of the English geologist. In case he 
used the word Recent in the Lyellian sense — this he does not seem 
to do exactly — he would ignore for the most part, if not altogether, 
the times designated by the term Post-Pliocene. And the question 
may be well raised, whether he does not give it less prominence than 
it deserves, — less importance than intrinsically belongs to it, not so 
much from its great length, as from the phases which it exhibits, and 
from the opportunity it furnishes for minute discriminations on ac- 
count of its proximity to the present. ‘The term Post-Pliocene is, 
at the same time, open to objection, (1) because a special limitation 
is needful, in order that it may not be understood to include the 
Recent, or all that follows the Pliocene; (2) from the inappositeness 
consequent upon the introduction of “ Plistocene” for “ Newer- 
Pliocene”; and (3) in view of the additional change suggested by 
the results of more recent investigations, that the Plistocene forma- 
tions are really Post-Tertiary, and accordingly need to be more 
emphatically discriminated from the older Pliocene, or Pliocene 
proper, which are strictly Tertiary. I have dwelt thus at length on 
this matter, since a great deal of vagueness is observable in many 
writers on the Post-tertiary times. 
In the light of what has been advanced there may be suggested, 
and as furnishing an outline for the remainder of this paper there is 
presented, the following classification of the Post-Tertiary forma- 
tions. This is thought to be in essential harmony with the facts, 
while it preserves the substance of the Lyellian nomenclature. This 
system is followed, not in approval of Sir Charles’s principles of 
classification, for these, as originally proposed, have lost their signifi- 
cance, but because his mode of designating the Cainozoic formations 
is more widely prevalent than any other, both in England and in 
this country. Reading from below upward, we have : — 
3. Autocene | Newer; Historic Period: — Forming Alluvium. 
(or Recent) ( Older; Prehistoric “ © — Ancient « 
Pe Holocene Te ewer; Peat Period : — Peat-beds, Mammoth, ete. 
Older ; Marl «© ;—Marl-beds, fresh water shells. 
Newer; Terrace Period : — Modified Drift, stratified 
1. Plistocene clays and sands. 
Older; Iee Period : — Typical Drift, unstratified. 
