806 y The American Naturalist. [September, 
` tended to be a geologist, and was led by thé resemblance in the 
fossil floras, without taking account of other kinds of evidence, 
to place most American plant-bearing deposits too high in the 
series. Why, for example, should Europeans continue to follow 
Lesquereux in calling the Laramie group Tertiary, when King, 
Hague, Emmons, Powell, Cope, Marsh, and almost everybody 
else, have always called it Cretaceous? Moreover, I have shown 
in my “Synopsis of the Flora of the Laramie Group,” published 
in the Sixth Annual Report of the U.S. Geological Survey, that 
the evidence of the fossil plants does not necessarily conflict with 
the latter view, and that the idea that it does so conflict arises 
from two causes: First, lack of attention to the character of the 
Upper Cretaceous floras already known; and secondly, the all em- 
bracing predominance of the Miocene flora of Europe, in which 
it is possible to find surviving types of the Cretaceous flora, and, 
indeed, almost anything that it is desired to find. 
Again, Professor Jankö does not seem to be aware that most 
or all of the Tertiary plant-bearing deposits of the Arctic and 
sub-Arctic regions which Heer classed as Miocene are regarded as 
Eocene by those who are now chiefly devoted to their study. 
Heer’s fallacy was also two-fold. Not only was he led astray by 
the abundance of the Miocene flora to which, as developed in 
Switzerland, he had devoted so much of his life, but he also 
failed to make sufficient allowance for the effect of high latitude 
in causing a flora to appear more recent than it is, as has been 
chiefly pointed out by Gardner. : 
The geological distribution of the fossil species according to 
Jankó, employing his own nomenclature with its exclusions, is as 
follows : 
Cretaceous.—P. primeva, primeva heeri, and newberryana. 
Eocene.—P. rhomboidea, raynoldsii, haydenii, and gulielme. 
Miocene and Pliocene—P. aceroides, aceroides academia, 
aceroides dissecta, gulielme, and marginata. 
He does not specify localities, and thus leaves the botanical 
reader to infer that all these statements are of equal geological 
weight, which is far from being the case. In fact, for reasons 
already given and many others, a large part of the whole argu- 
