GEOLOGICAL ANTIQUITY OF FLOWERS AND INSECTS. 
47 
species is extraordinarily small. Remains of insects, their wings, 
legs, heads, &c., are preserved as we have seen ; and there is no 
reason why we should not have found dicotyledonous flowering 
plants had they been abundant. 
In a Greenland formation which Professor Heer calls Lower 
Cretaceous, plant beds are found which have yielded extraordinary 
results; 138 species of ferns, 75 of monocotyledonous flowering 
plants, and one dicotyledonous plant have been described. In 
the greater part of Europe the Cretaceous period was marked 
by deep-sea conditions, so that we have little expectation of 
finding fossil land plants. The Upper Cretaceous formation in 
many places seems to have been favourably deposited for the 
preservation of these desirable plants. It should be stated, 
however, that in the opinion of some geologists some of the so- 
called “ Upper Cretaceous ” beds, especially those of Dakota, 
are regarded as possibly intermediate in age between the 
Cretaceous and Eocene, so that they form “ passage-beds ” between 
the Secondary and Tertiary epochs. The most remarkable strata 
of these deposits are perhaps those of Dakota in the Western 
States of America, whose fossil plants have been figured and 
described by Professor Lesquereux. Here we find no fewer than 
one hundred species of dicotyledonous plants. In the Aix-la- 
Chapelle beds a large number of fossil leaves, &c. have enabled 
botanists to chronicle the incoming of many orders of plants at 
an earlier date than had been before imagined. In tropical 
Africa and Greenland plant-bearing beds of so-called Upper 
Cretaceous age have also been explored ; and the occurrence 
of the remains of monocotyledonous and dicotyledonous plants 
in them proves how widespread and abundant these groups had 
already become. 
All the coniferous and most of the monocotyledonous plants 
are “ wind-fertilized ” ; and it is probable that up to the begin- 
ning of the tertiary epoch no such beautiful perianthed mono- 
cotyledons as the lilies, tulips, &c., had made their appearance 
— that, in short, all the monocotyledonous plants were up to 
that time “ wind-fertilized.” It is curious to note that when 
the dicotyledons first make their appearance it is also the 
“ wind-fertilized ” group which comes first. Thus, in the Upper 
Cretaceous beds of Dakota, out of the one hundred species of 
dicotyledonous plants described, no fewer than sixty-one are apeta- 
lous , such as the oaks, maple, &c. (see figs. 1 & 2). Many of them 
were catkin bearers, as the poplars. Of the remainder, thirty- 
five species are those possessing polypetalous flowers ; whilst only 
one species is gamopetalous — that is, has flowers with the petals 
united into one piece. The proportion of “ wind-fertilized ” over 
“ insect- fertilized ” plants is always greater the farther we go 
back in geological time, thus indicating that the “wind- 
