FERNS, FOSSILS AND FUEL 
covered the land in the distant prehistoric past. The only 
feature that we cannot be quite sure about is the color. 
We have learned what we know about the dinosaurs 
and other prehistoric animals from their bones and 
skeletons which have been preserved, in one way or 
another, in various parts of the world. The vegetation 
of former ages has left much the same sort of skeletal 
remains in botanical fossils. Such fossils are pieces of 
rock which bear the impression of a leaf or a stem, or 
even of a whole plant organism, embedded in them. 
They are a petrified record of something that lived during 
a previous geologic age. 
The science which is concerned with these fossil plant 
remains, with the arrangement of the fragments into the 
whole plant that actually grew, and with their classifica¬ 
tion, is called paleobotany, the science of ancient plant life. 
Its background is necessarily a combination of botany 
and geology, as the name implies, but it is much more 
than just a combination. The science is a comparatively 
new one; it is interesting to trace its development in the 
United States. 
When Louis Agassiz arrived in America in 1847 to 
take the chair of natural sciences in Harvard University, 
he had left behind him in the historic Swiss town of 
Neuchatel a man who had been closely connected with 
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