568 On the Age of the Laramie Formation. [ August, 
collecting in the Gault, at Folkstone, for twenty years, during the 
latter part of which I have employed, constantly, a collector, goes 
far to show that up to that period dicotyledons did not exist, in 
these latitudes at least. Five new species of cones, branches of 
conifers with leaves attached, resin and coniferous wood are found, 
the latter abundantly, but no dicotyledons.” I cannot but believe 
that had dicotyledons existed, some trace of them would by this 
time, have been found. The same is true of the Gault elsewhere, 
and especially in Hainault, where a more abundant flora has been 
brought to light. Neither in Neocomian, Gault, Upper Green 
sand or chalk, or any Cretaceous deposit in England, has any- 
thing leading to the supposition that dicotyledons were then in ~ 
existence, yet been found. Dicotyledons may have been develop- 
ing in other‘areas at this or an earlier period, especially towards 
the Poles, but from the evidence of British rocks, I should refuse, 
in the absence of confirmatory stratigraphical evidence, to assign 
so great an antiquity as that of our chalk to any deposits contain- 
ing dicotyledons in our latitudes. If clearly older than our 
Eocene, I should refer them to the great intervening period. 
From the almost complete absence of Cretaceous forms in even 
the lowest European Tertiaries, it seems to have been concluded 
everywhere, that all rocks containing even a small proportion of 
Cretaceous types, must be classed as of that age. Isolated pro- 
tests have been raised, but their value has not been felt. This 
basis of classification is, in my opinion, entirely erroneous, or at 
least carried to an excess, for all we know is, that the fauna which 
existed in Cretaceous seas did not exist in those of the Eocene. 
* How or when it disappeared from these areas we do not know. 
The extinction, or perhaps partly migration, must, however, have 
been a natural and gradual one, and we see in many distant coun- 
tries, California, New Zealand, India, Vancouver's Land, 
instance, that late Cretaceous types of fauna lived long after va 
time of which we have any record -of them here, and mingled 
with a fauna whose characteristics are decidedly Eocene. 
For the reasons already advanced I should regard the flora of 
Dakota, together with those of Nebraska, Vancouver's Land, 
New Zealand, and many European floras, characterized by an 
abundance of dicotyledons, as belonging to a vast intermediate 
period, and should adopt a name suggested by Hector for it— 
Cretaceo-Eacene—in preference to the term Pal-Eocene, used by 
we 
