THE ADVENT OF FLOWERING PLANTS 
tions destroyed and overran the Roman empire, the flow- 
ering plants, with an almost explosive expansion, took 
possession of the surface of the earth and established them¬ 
selves as the dominant type, a supremacy which they have 
held to our own day. 
We can reconstruct an Upper Cretaceous flora from 
the Dakota sandstone deposits in Kansas. The type for¬ 
mation of the period is in South Dakota, hence the name, 
but the deposits are much more extensive in Kansas. 
The flora of the period was a sub-tropical one such as 
we see today near the Mississippi delta or in the West 
Indies. Most of the genera which grew then are rep¬ 
resented in the living flora of today, but by other species. 
Magnolias, tulip trees, myrtles, viburnum, oaks, beeches, 
elms, sassafras, and a great variety of Ficus, of which 
the best known living representatives are the fig and rub¬ 
ber trees, were all prominent. There were sweet gums 
and sycamores, and many primitive and now extinct 
angiosperms. 
We know from this horizon only the trees and shrubs. 
We are not familiar with the small plants growing in 
the meadows and forming the undergrowth of the forests. 
Only the organs that fell from the trees and bushes had 
a chance to be imbedded in the sand which later became 
sandstone and so beautifully preserved even the finest 
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