IOWA ACADEMY OP SCIENCE 
165 
running an entry. When this latter work is in progress is the time for 
special search for these rare fossils. 
Four locations have thus been ascertained where the conditions are favor- 
able for the preservation of fossils in an excellent manner. Undoubtedly 
search with this point in view will bring to light many other places In the 
Des Moines formation. I think it probable that many specimens are over- 
looked or thrown aside in the mines which if saved could add much to our 
knowledge of the upland Carboniferous flora. 
