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POPULAR SCIENCE MONTHLY 



dreds of species. Sometimes very striking structural characters may 

 be observed; but when assistance is sought from the literature on living 

 forms, the student finds that characters of this class have been ignored, 

 and it is necessary to make a fresh study of the modern genera before 

 proceeding with the fossils. In order to do this, however, large collec- 

 tions are needed, and it is no easy matter to secure sufficient specimens. 

 Thus, in one way and another, the opportunities for error in the study 

 of fossil insects and plants are very many; so many, that it is easy to 

 become discouraged, and yield to the temptation to confine oneself to 

 the comparatively easy problems presented by modern types. In such 

 times of discouragement, however, the student may be cheered by the 

 discovery of some splendid thing, telling a tale beyond dispute; and so 

 he returns to his labors, determined to unravel the secrets of the past, 

 and to accept as philosophically as may be the inevitable results of his 

 inability io avoid a certain percentage of error. 



In an effort to reconstruct the landscape of the Miocene period in 

 Colorado, we may well begin with the plants. The number of fossil 

 plants described from Florissant is not nearly so great as that from 

 (Eningen ; but the deposits of the latter locality are, apparently, not 

 so nearly contemporaneous; while, on the other hand, not nearly all 

 the Flor'ssant species that have been found have yet been published. 

 The collections of the 1907 expedition, rich in new materials, have only 



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Fossil White Ant (Hodotermea coloradenaia of Scudder). 



