CHAPTER TWENTY 



THE FLORISSANT SHALES OF COLORADO 



1. NEAR the western base of Pike's Peak, almost TheFioris- 

 under the shadow of that great mountain, lies the santVaUe y 

 Florissant Valley. It is an upland region, over 8000 



feet above the level of the sea, with grassy meadows 

 and rocky slopes, and granite hills all around. Super- 

 ficially it resembles many of the smaller so-called parks 

 of Colorado, and there is little about it to attract atten- 

 tion. It is, nevertheless, one of the classic localities 

 of the world, known to geologists and paleontologists 

 everywhere, mentioned in all geological textbooks, 

 though, like a prophet in his own country, unheard of 

 by most of the people of Colorado. Here may be found 

 preserved the life of a million years ago : leaves and 

 flowers, butterflies and beetles, in many cases almost 

 as perfect as when alive, so that the most minute struc- 

 tures can be seen with the aid of a microscope. 



2. During the Miocene Period, long before the ap- The ancient 

 pearance of man in the world, there was a large lake, 

 shaped rather like the letter L, at what is now Florissant. 



In those days it is probable that the elevation was 

 less than 8000 feet ; possibly much less, since we know 

 that the Rocky Mountains have been steadily rising 

 during the last few millions of years. Whether they are 

 still going up, we cannot tell, as any slight difference 

 from year to year would be too small for us to measure, 

 in the absence of any visible stationary point for com- 

 parison. The climate was moister and warmer, more 

 like that of the Southern states today, but not tropical. 

 This we know from the character of the vegetation. 

 Around the lake were active volcanoes, which sometimes 

 threw out very finely divided ash, sometimes liquid 



