320 JESSEVE. AY DE 
ADJUSTMENT OF THE SURROUNDING SEDIMENTS TO THE CHANGE IN 
VOLUME 
At the time of the compression of the coal to its present volume 
or near it, some adjustment in the distribution of the adjacent sedi- 
ments was necessary. This was accomplished, perhaps almost 
entirely, by flowage in the underlying soft clay shales, which slowly 
bulged upward beneath the coal deposits as their bulk became less, 
and came to form the shale crests which are capped by the coal. 
This is demonstrated by the fact that where thin sandstones are 
present in the shales, they are distinctly arched upward in these 
crests (Fig. 4). The sandstones over the coal are undisturbed 
except where they are interbedded with thin coals which have also 
suffered compression. On the side of one of the shale crests and in 
contact with the shale, they show flowage lines similar to slicken- 
sides, caused by the upward movement of the shale. There is 
evidence at one point that some of the movements of readjustment 
were abrupt; shales with a few thin sandstone beds are turned 
upward at a sharp angle for several feet so that their edges rest 
against the nearly horizontal bottom of the overlying main bed 
of sandstone. The bottom of the sandstone in this case carries the 
impression of the upturned thin sandstone layers of the shale series. 
These occurrences are believed to demonstrate that the massive 
sandstones were not consolidated at the time of the readjustment. 
EFFECT OF INCLINED BEDDING IN DETERMINING THE AMOUNT OF 
REDUCTION 
The most remarkable feature of the entire deposit is found in 
the inclined bedding of the thick sandstones, and in its relation to 
the coal pockets. The inclination of the bedding throughout most 
of the cut is toward the north and northeast, and usually at a low 
angle, commonly from 5° to ro. At the south end of the cut the 
inclination is changed for a few yards to southeast. At the north 
end, just at the point where the outcrops become obscured by the 
low gentle covered slopes of the shallower part of the cut, the 
sandstones appear to have been derived from the northeast. The 
occurrence shown in Fig. 4 is found where the material from the 
two directions met. 
