172 ANNALS NEW YORK ACADEMY OF SCIENCES 
Feet Inches 
varies from regular to indefinitely cross-bedded; remains of 
plants abound; they were deposited in accord with the bedding, 
where that is regular, but elsewhere in all directions, with or 
across the lamination. 
7. Coal, Banc inferieur .5 7 
This is less easily separated from the portion below than in Foret; 
the partings are many and the lenses of sand and clay are more 
numerous. At some exposures, these lenses are so abundant and 
extensive that one could easily regard the whole deposit below the 
Banc des Roseaux as belonging to No. 8. 
8. Coal and rock, Banc des Brouillages (seen).5 0 
This has the same characteristics here as in Foret. The surfaces 
of its rock layers are broadly wrinkled. 
The Banc superieur is not mined. At all exposures in the several 
trenches, it shows the same irregularity of structure and the same abundance 
of mineral matter. It is exposed for a long distance at the foot of the 
westerly wall, where it is from three to seven or eight feet thick, and the upper 
surface is so irregular that one could well imagine himself looking at the 
cross section of hummocks. The many petty faults and breaks in the bed 
along this exposure are due mostly, no doubt, to removal of the coal below, 
but the hummock-like form is not due to that cause for it is equally distinct 
where the main coal is still in place. An open cut, midway in the trench, 
represented by Plate XV, figure 2, shows this feature of the bed. In that 
opening one finds 
Feet 
1. Banc intermediate . 14 
2. Banc des Roseaux .2 to 6 
3. Banc inferieur . 11 
4. Banc des Brouillages (seen) . 2 
The middle division is exposed in an almost vertical wall, so that exact 
measurement could not be obtained. The Banc des Roseaux is thin towards 
the present outcrop but thickens down the dip — a somewhat unexpected 
condition. The Banc inferieur seems to be mostly good coal and contains 
very few of the sandy lenses, which are so abundant at less than 300 feet 
away. It is separated from the Brouillages by a bed of shale. 
The Banc des Chavais has become very indefinite at this exposure and 
at another, only 30 feet farther, it has disappeared so that the middle and 
upper beds are continuous; still farther is another, showing at least IS feet 
of coal above the Banc des Roseaux. 
This trench was carried down to its present depth on the coal and then 
the bed, dipping at 20 degrees and upward, was uncovered by stripping in a 
space more than 100 feet wide. The Banc inferieur is exposed along the 
easterly side for not far from 100 feet in a shallow trench, where it is folded 
