1891.] 
213 
[Marcou. 
of New York, has been the tool constantly used by unskillful 
hands to classify strata absolutely different in every respect from 
those with which they have been identified. 
Few paleontologists are able to deal with stratigraphy and 
lithology. I shall name only a few of the dead, such as : Edward 
Forbes, Barrande, Alcide d’Orbigny, Quenstedt, von Buch, Oppel, 
Newmayr, Linnarson, E. Emmons, Conrad, de Verneuil, David 
son, Salter, etc. But unhappily many paleontologists, not so 
skilful as those iust named, have tried to classify strata with 
either incomplete data, or with incorrect determination of species, 
of genera and even of family ; and without hesitation they have 
given and used classifications of strata incorrect and at complete 
variance with the facts as they exist in situ. Of course the rocks 
are there plainly exposed to view, and observers can go any day 
and see for themselves. Obstruction cannot last very long, and 
first-rate paleontologists, although rare, are sure one day or an- 
other to take in hand all the questions at variance, and to see 
that paleontology properly understood and used, is in complete 
harmony with the result arrived at by stratigraphists and practi- 
cal geologists. 
A quotation taken from “Life and letters of A. Sedgwick,” by 
Clark and Hughes, vol. ii, pp. 397-398, Cambridge, 1890, applies 
most fittingly to the case. It reads as follows : “ . . . No good 
classification either of subdivisions or systems, or of subordinate 
formations, ever can be attempted wfithout a previous determina- 
tion of the physical groups. The study of fossils, based on ascer- 
tained physical groups, may produce, and often does produce, 
some modification of our lines of demarcation ; but the evidence of 
sections must ever remain as the primary basis of geology. When 
a system has been well made out, and its groups of fossils deter- 
mined, we may then make use of comparative groups of fossils 
freely, and with very small risk of mistake. But to begin with 
fossils , before the physical groups are determined , and through them 
to establish the yiomenclature of a system , would be to invert the 
whole logic of geology , and could produce nothing but confusion and 
incongruity of language.’’ 1 The italics are mine. Dr. Emmons 
and the present writer have followed strictly Sedgwick’s rules, 
while their opponents on the contrary have “inverted the 
whole logic of geology,” with the constant result of “confusion 
and incongruity of language.” 
