THE LITTLE MISSOURI BAD LANDS. 



473 



spontaneous combustion supplies the torch, and the whole phenomenon 

 is explained. 



That the lignite is in some way connected with the fiery metamor- 

 phosis of the Bad Lands we might have inferred from the fact that no 

 lio-nite ever appears above the burned belts, and in a hill entirely 

 burned the lignite is entirely wanting. The burned clay also corre- 

 sponds in position to beds overlying the coal in hills immediately ad- 

 jacent. But, as we have said, the fires in isolated spots are still burn- 

 ing ; in some places wholly subterranean, smoldering and smoking, 

 at other points readily seen both in nature and effects. We may dis- 

 cover the coal on one side of a broad-topped hill, and on the other we 

 may look from the hill's summit down through gaping rifts to the 

 same horizon and see everything molten at white heat, while hot air, 

 smoke, and coal-gas, as from a furnace, make the region almost inac- 

 cessible. The accompanying diagrams (Figs. 2, 3) illustrate a burn- 



Fig. 2. Transverse Section of Burning Lignite Thickness op Lignite-Bed exaggerated. 



ing coal-bed, which has been photographed and dubbed " The Crater." 

 Here the fire is burning out the lignite beneath a valley lying between 

 two rounded ridges. As fast as the coal is removed by combustion 



: J5 sgk& 



Fig. 3. Longitudinal Section op Burning Lignite Thickness op Lignite-Bed exag- 

 gerated. 



the whole section of the valley sinks, creating with respect to the 

 stratification what geologists term a, fault. At the lowest part of the 



