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Floor-case No. 6 encloses plant remains from the rocks 
of later Mesozoic time: Lower and Middle Cretaceous 
Period. These specimens represent the first appearance 
of the higher-seed-bearing plants (Angiosperms), the type 
which is dominant in the existing flora. The genera are 
in most instances apparently identical with those now in 
existence, but the species are extinct. The plants of the 
Lower Cretaceous consist largely of ferns and cone-bearers, 
while those of the middle Cretaceous show a preponderance 
of angiosperms. 
Floor-case No. 7 is arranged to show specimens of the 
Middle Cretaceous flora found within the limits of the 
City of New York, on Staten Island, or in the immediate 
vicinity in New Jersey and on Long Island. 
Floor-case No. 8 contains specimens from the Middle 
Cretaceous of the western States. ‘Those from the Dakota 
Group are exceptionally fine, many of them being perfectly 
preserved and showing both case and impression of the 
same leaf as counterparts. 
Floor-case No. g is devoted to plants of the Upper 
Cretaceous (Laramie Group), and completes the vegetation 
of Mesozoic time. 
Floor-cases Nos. 10 to 12 and wall-case No. § contain 
plant remains of Neozoic time. Those of the early Ter- 
tiary Period (Eocene) are displayed in floor-case No. Io. 
Those of the later Tertiary (Miocene) and Quaternary 
Periods in floor-cases Nos. 11 and 12. The specimens in 
the latter case complete the sequence of plant life on the 
earth and bring it up to modern times. A number of 
specimens at one end of the case show the methods of 
preservation by petrifaction, incrustation, and carboniza- 
tion, and on the upper shelf is a series of specimens from 
Quaternary and more recent swamp deposits which show 
how the conversion of living plants into fossils, a process 
now going on, has its beginning. 
The specimens in wall-case No. § further illustrate the 
characteristics of the plants of the late geological periods 
