126 THE FLORA OF THE AMBOY CLAYS. 
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flower with twenty or more ray-florets. It is evident, however, that the 
material composing these: florets of the ray was more substantial and per- 
sistent than that of most helianthoid flowers, but it is well known that many 
of the Composite, like Gnaphalium, Heliochrysum, ete., have the ray- 
florets searious or woody, and large flowers of the latter genus buried up in 
mud and then baked would present practically the same aspect and exhibit 
apparently the same structure as these. 
But it is well known that the Composite are among the most special- 
ized and, as we say, the highest, of the flowering plants, and it would 
require some modification of the generally prevalent ideas of the progress 
of plant life on the globe to suppose that plants as highly organized as 
any at the present time were not only present but abundant in the flora 
that dates back to the middle of the Cretaceous age. And yet our explora- 
tion of the Cretaceous flora has been full of surprises like this. That 
the forests of North America at the date of the deposition of the Dakota 
sandstones and the Amboy Clays were largely composed of trees which in 
size, beauty, and botanical rank would compare favorably with the constit- 
uents of our forests at the present day is indisputable. Magnolias and 
Liriodendrons, the ornaments of our present forests, were there in abun- 
dance and apparently in their greatest development, because they were 
represented by a larger number of species than are found living at the 
present time. The Liriodendrons were not only more numerous but more 
varied and specialized, and it is evident that they were then in the golden 
age of their existence. So the Sassafras, the sweet gum, and the Aralias, 
and all the other conspicuous elements in this flora are of relatively high 
botanical rank. Hence, in such a flora, flowers of the Composite would 
not be out of place, and we should not hesitate to accept the obvious infer- 
ence that these were such if it were not that a group of flower-like organs— 
1 mean the flowers called Williamsonia—had been found in the Mesozoic 
rocks, possibly as low as the Trias, which are not without resemblance 
to, and perhaps not without botanical affinity with, these, and which have 
been proved to be the florescence of cycads. The flowers of Williamsonia 
have given rise to much discussion and have been regarded by botanists 
as representative of very different botanical groups. For example, Professor 
