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and their allies (Pteridophyta) represented by Lepedodendron, 
Sigtlaria and Calamites, and the early seed-bearing plants, 
the cone-bearers (Gymnosperms), represented by Cordattes, 
with the fossils under 77igouocarpon, Rhabdocarpon, and 
other genera. 
In the second floor-case are representatives of Palaeozoic 
Time: Carboniferous Period. —The specimens in this case 
are exclusively ferns or plant-remains which were originally 
described as ferns but which are now thought to belong to a 
different group, the Cycadofilicales, that is, plants that had 
characteristics of both the ferns and the sago-palms, but 
rather more closely related to the cone-bearing trees than to 
the ferns. 
The third floor-case contains types of Mesozoic Time: 
Triassic and Jurassic Periods. — The plant-remains in this 
case are mostly sago-palms or cycads, with some other cone- 
bearers and fern-plants. 
The fourth floor-case embraces plant-remains from the 
rocks of Mesozoic Time: Lower and Middle Cretaceous 
Period. — These specimens represent the first appearance of 
the fruit-bearing plants (angiosperms), the type which is 
dominant in the existing flora. he genera are in most in- 
stances apparently identical with those now in existence, but 
the species are extinct. The plants of the Lower Cretaceous 
period consist largely of ferns and cone-bearers, while those 
of the Middle Cretaceous show a preponderance of seed- 
bearers. The specimens from the Dakota Group of Western 
America are exceptionally fine, many of them being perfectly 
preserved and showing both cast and impression of the same 
leaf. 
The fifth floor-case contains the plant remains of Mesozoic 
Time: Middle and Upper Cretaceous Period. Here may 
be seen interesting specimens of the fossil floras of both 
eastern and western North America, including the ancestors 
of our living tulip-tree (Zzrzodendron). 
In the sixth floor-case may be seen the plant-remains of 
Neozoic Time: Tertiary, Quaternary and Recent or Modern 
