LL. Lesquereux—Coal Beds of the Rocky Mountain region. 29 
Art. VIIT.—On the Formation of the Lignite Beds of the Rocky 
Mountain region; by L. LesQuEREUX. 
FRoM a report which is apparently reliable, but which I have 
not seen in print yet, a prominent geologist has advanced the 
opinion that the so-called lignite beds of the Rocky Mountains 
have been formed by the heaping of drifted materiais. This 
ag Says my informant, is sustained by the following 
acts : 
Ist. That the lignite beds are of too small extent, or cover 
too limited areas, to have been formed otherwise than by 
the heaping of materials carried into small basins. 
d. That the under clays of the lignite beds have no roots. 
I do not wish, of course, to review the old hypothesis on the 
formation of coal and lignite, as exposed in a masterly manner 
and sustained by Bischoff; but only to answer the two above 
objections. 
Creek, and has been tested all along for a distance of pine miles; 
and northward the same bed is recognized continuously for 
Seventeen miles to north of Boulder Creek, where it is covered 
a of lignite measuring generally from eight to fourteen feet in 
thickness. The Heniee be : ro- 
ably and locally reduced in extent the area of strata of com- 
ustible materials, and broken their continuity. The large or 
thick main coal of Black Butte has been destroyed in this way 
©n its eastern side; and here its shale and sandstone are meta- 
morphic, or as hard as steel, while on the other side, where the 
coal has been preserved, they have their natural softer composi- 
