164 
ANNALS NEW YORK ACADEMY OF SCIENCES 
ascertained that there are five distinct zones or areas of deposit, in each of 
which the material has its special features; these are not successive, but are 
distributed geographically and merge laterally; they are of synchronous 
origin. Three of these zones, Longeroux at the east, Montassiege midway 
and Bourdesoulles at the west, contain for the most part, coarse materials; 
while the zone of les Pegauds, between Longeroux and Montassiege, and 
that of les Ferrieres, between Montassiege and Bourdesoulles, contain 
mostly fine materials. The several areas extend from north to south, 
except that the two containing fine materials are cut off at the north by a 
narrow strip of coarser beds lining the basin on that side. 
Coal is' confined, practically, to the areas of finer deposits. In these 
The heavy black lines indicate coal. This map differs from that in the original 
work in the extent of the Pegauds and Ferrieres areas: the original map made those 
embrace the whole of the great bed in each case — and in that respect is the more 
nearly correct. 
the lower rocks, 500 to 800 meters thick, are almost barren, containing only a 
few irregular streaks of anthracite, which appear to be without commercial 
importance. The coal is mainly in a single bed within each area, which has 
a curved outcrop rudely resembling the letter “C,” and thins southwardly 
so as to disappear midway in the basin. Near the northern outcrop, each 
bed attains an enormous thickness, at times more than 60 feet; the southern 
boundary is defined approximately by a line joining the extremities of the 
outcrop. The rocks above the great coal bed in each area are reported to be 
increasingly coarse but are interrupted by shale carrying coal. They nowhere 
become as coarse as the beds of the other areas. The extent and distribu¬ 
tion of the several zones or areas are shown in Figure 1, which is based on 
