278 EEPORT OF THE AMERICAN COMMITTEE. 
the noD -characteristic nature of those that liave been discovered, 
the age of the Grand Gulf beds is still an open question. 
LATER TERTIARY. 
Concerning the later Tertiary deposits, I have at present no 
report to make, and the attention of the reader is invited to the 
note of Prof. Dall in the Appendix, in which it will be seen 
that we are as yet very far from having a satisfactory arrange- 
ment of the later Tertiary formations of the Atlantic coast. 
Concerning the Tertiary formations of the Pacific Coast I have 
also no report to make at this time. 
In the Appendix are presented the views of a number of the 
Geologists of the United States, who have made the Tertiary a 
subject of special study, upon the classification and nomenclature 
of the deposits of this age. 
Dr. Eugene Smith 
NOTE. 
Philadelphia, July 29, 1887. 
Dear Sir : In response to your request for suggestions bear- 
ing upon the classification of the Tertiary deposits, I would re- 
spectfully submit the following : 
The first important question touched upon by the Interna- 
tional Congress (Rep. Am. Cora., p. 61) is whether the Tertiary 
forms the last of the geological systems ; otherwise stated, if it 
is followed by a Quaternary System. There is nothing, it ap- 
pears to me, either stratigraphic, lithologic or paleontologic, 
which permits us to recognize a Quaternary System as something 
apart from the Tertiary. A true classification of geological time 
must be based almost exclusively upon faunal characters, since 
these alone afford us criteria applicable to the world at large. 
Recognizing this fact, it must be manifest, if our conceptions of 
the Tertiary be correct, that the Quaternary is a part of this 
system, since, faunally, it is much more intimately related to the 
Pliocene than the Pliocene to the Eocene, members of one and 
the same system. 
Recognizing, then, the Quaternary to belong to the Tertiary 
series, it will be admitted that all the Post-Cretaceous deposits 
