FLORISSANT; A MIOCENE POMPEII 



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Fossil Tsetse Fly (Glossina oligocena) . The tsetse flies are no longer found 



in America. (Much enlarged.) 



scarcely visible at all, especially on the wet shale as it is dug out; but 

 under a strong lens they show every detail of the structure of the wings. 

 On the other hand, some specimens which superficially appear excellent 

 prove upon minute examination to be of small scientific value. 



When the fossils have been obtained, it is no easy matter to deter- 

 mine and describe them. In the case of the plants, many species are 

 easily recognized and can be classified with much certainty; but there 

 are living species of oaks and maples, for example, which possess foliage 

 wholly unlike that which we usually associate with those names. A 

 maple from Japan, judged by its leaves, would be taken for a hornbeam ; 

 some oaks resemble willows. The commonest leaf in the shales was 

 considered by Lesquereux to be allied to the water elm of the southern 

 states; but we have found some pieces with the fruit attached, and it 

 seems to be a beech. Calyces, once supposed to belong to persimmon 

 or some allied plants, prove to be those of a poplar; while the giant 

 redwood itself was first introduced as a moss, from a fragment of a 

 twig ! 



The insects, when well preserved, offer much better characters than 

 most of the plants. Unfortunately, however, they are frequently in- 

 distinct or fragmentary, and the accurate determination of the remains 

 becomes extremely difficult. Only those who have worked on fossil 

 insects can appreciate at their proper value the tremendous labors of 

 Scudder, resulting in the description and classification of many hun- 



