BROOKLYN BOTANIC GARDEN RECORD 
VOL. XX! OU Eyer at9 32 NO. 4 
AEP SeORAe Or. FOSS BilbwNies 
GUIDEs LO Eh TRANSPARENCIES IN GCONSERVA= 
hOkKY HOUSE, NO: 
3y Epwarp W. BERRY 
Professor of Paleontology 
The Johus Hopkins University 
The earth has been recording its autobiograp 
hy for millions of 
years in the rocks of its crust, the estimates from the study of 
radioactive minerals giving figures somewhere between 1500 and 
2000 million years since it was of the size and form that it is today. 
The study of this autobiography is the science of geology, and it 
needs but understanding wedded to imagination to make much of 
this vast history intelligible. Through at least two thirds of these 
eons life has been present and has contributed its records to the 
sedimentary rocks. 
Almost everyone is familiar with some phases of evolutionary 
discovery among animals, such as has been worked out for the 
horse, camel, or elephant, but that plants have a similar evolution 
is hardly realized. Most people, if they give it a thought, think 
that the earth was always mantled with verdure as it is at present. 
They may know that all animal life is dependent on the organic 
food which plants, with the aid of the sun’s rays, elaborate from 
inorganic substances, but this does not mean to them that plants 
must be older than animals, nor do they realize that the evolution 
of the flowering plants conditioned the evolution of warm blooded 
animals, or that it was the concentrated food stuffs in the seeds of 
flowering plants which made agriculture and hence human cetvili- 
zation possible. 
* A “Note on the Preparation of the Transparencies”? may be found on 
the last page. 
209 
