C. A. White—Burning of Lignite in situ. 25 
making observations upon the phenomena connected with the 
burning out of lignite beds there. In that portion of Montana 
which is traversed by the lower portion of Yellowstone River, 
the Laramie Group contains several distinct beds of lignite 
which oceur at irregular intervals, ranging from near the base 
of the group to its summit. These lignite beds vary from 
mere carbonaceous seams to five or six feet or more in thick- 
ness. Practical tests that have been made of the product of 
many of the beds show it to be readily combustible, but it is 
not so durable and serviceable a fuel as could be desired. In 
all that région, not only in the valleys but upon the uplands, 
the Laramie strata have by erosion become abundantly ex- 
posed in the bluffs and bad-lands in and near the valleys, and 
also in the knolls and gullies upon the upland surfaces. Beds 
of lignite are frequently brought to view in the larger of these 
‘exposures and traces of them are also occasionally seen upon 
the grassy upland surfaces. Although the beds have been 
red at hundreds of places it is only in a few places that those 
which are now exposed are seen to have so suffered near their 
present exposures, 
In several instances, however, I was able to trace within a 
short distance, a bed of lignite from a point where it was un- 
changed and associated with yellowish and carbonaceous sandy 
shales and sandstones both 
Set ang near by presented a like appearance with that which 
as just been described, and where the fire had been long 
here being no question as to the fact of the burning of 
these lignite beds beneath the surface, I endeavored to learn 
how the ignition had taken place, and when the beds began to 
be ‘burned out. There seems to be only two ways in which 
their ignition could have been accomplished. One is by spon- 
heous combustion and the other by contact at exposed places 
of prairie fires, or fires caused by human agency. hile 
