

uk to 

represent the taney ae of the Cretaceous and the iota 
of the Tertiary. This question is at the same time one of consider 
difficulty, so much so, that the systematic position of a great serie 
beds, in some places several thousand feet in thickness, and including 
the greater part, if not the whole, of the valuable lignite deposits, is 
present in doubt. Various geologists who have devoted much time and i 
study to the formation, are almost equally divided in opinion as to the 
Cretaceous or Tertiary age of the rocks, or the correlation of a portion — 
with the former and a por tidh with the latter formation, and the position — i 
of the separating line. aa es: 
434. Much of the difference of opinion, however, appears to have ye. 
arisen from approaching the problem with preconceived ideas, and the 
attempted application of paleontological generalizations derived from ie z: 
the study of other localities, which have been formulated under too rigid 
laws. The break between the Cretaceous and Tertiary in England, and 
in Europe generally, is one of the most complete and striking in the 
entire rock series, and justifies not only the strict separation of the 
Upper Cretaceous and Eocene beds, but the introduction of the great — E } 
classificatory line dividing the Secondary from the Tertiary. The © 
Meestricht and Faxoe beds, and the Pisolitic limestone of France, it is — ai 
true, show an approximation to the fauna of the Eocene, but are still ‘ 
distinctly Cretaceous, and go but a little way toward bridging the great mee 
hiatus between the formations. The Upper Cretaceous beds of New 
Jersey, and the interior continental region, appear to represent these 
highest European members of the Cretaceous; and in the eastern coast 
region of America the localization of the break between the Cretaceous | 
and Tertiary at this horizon is also borne out, the lignitic series of the ie ii 
Se 
West being unrepresented. ay 
































435. It has been a common paleontological aphorism, based - 
especially on the study of the European series, that no single species | f: S 
is known to have passed upward from the Cretaceous to the Tertiary, 
but this, like most negative generalizations in geology, is already found 
to be imperfect. On examining the typical localities, we find that the 
change in the form of life is not alone, but synchronous with vast 
physical changes, indicated by an entire alteration in the character of 
the deposits. There is every reason to believe, that the physical break 
was more sudden and potent in its effect on the forms of life, than any 
slow replacement of old types by new, by development or otherwise. 
