THE YELLOWSTONE NATIONAL PARK 65 



new soils for forests, gardens, and meadows. 

 While this ice-work was going on, the slumber- 

 ing volcanic fires were boiling the subterranean 

 waters, and with curious chemistry decomposing 

 the rocks, making beauty in the darkness ; these 

 forces, seemingly antagonistic, working harmo- 

 niously together. How wild their meetings on 

 the surface were we may imagine. When the 

 glacier period began, geysers and hot springs 

 were playing in grander volume, it may be, than 

 those of to-day. The glaciers flowed over them 

 while they spouted and thundered, carrying away 

 their fine sinter and travertine structures, and 

 shortening their mysterious channels. 



The soils made in the down-grinding required 

 to bring the present features of the landscape 

 into relief are possibly no better than were some 

 of the old volcanic soils that were carried away, 

 and which, as we have seen, nourished magnifi- 

 cent forests, but the glacial landscapes are incom- 

 parably more beautiful than the old volcanic 

 ones were. The glacial winter has passed away, 

 like the ancient summers and fire periods, though 

 in the chronolgy of the geologist all these times 

 are recent. Only small residual glaciers on the 

 cool northern slopes of the highest mountains 

 are left of the vast all-embracing ice-mantle, as 

 solfataras and geysers are all that are left of the 

 ancient volcanoes. 



Now the post-glacial agents are at work on the 



