THE FLORISSANT SHALES OF COLORADO 



'59 



Photograph from American Museum Journal 



FIG. 32. Fossil flower (Parana cockerelli, Knowltonl from the Miocene shak-s of 



Florissant. Enlarged. 



fossils were thus destroyed, we can never know, but 

 the amount of fossiliferous material still remaining is 

 very great. At various places along the sides of the 

 valley the shale is either exposed, or is readily reached 

 by digging. On the surface it is usually weathered and 

 spoiled ; but by digging a trench good shale may often 

 be found, and when carefully split by hitting the edge 

 with a knife, it will show broad surfaces which may or 

 may not reveal fossil remains. Collecting fossils in this 

 way is laborious and often disappointing, but some- 

 times a single stroke of the butcher knife shows a speci- 

 men which carries back the history of some group of 

 plants or animals a million years. After many days 

 of work, the collections always prove to contain species 

 new to science, and there are few localities which yield 

 such good returns. 



