166 SUBDIVISIONS OF THE CARBONIFEROUS SYSTEM 
ters, and may be described as local series. Whereas each 
particular basin of Carboniferous rocks or sediments may have 
its own particular conditions of sedimentation which led to 
peculiar local differences existing between the several basins 
which may be under examination and comparison, there can be 
no doubt at all about the series belonging to the Carboniferous 
System, when the results obtained in Great Britain, France: 
Germany, and the world over, have been consulted. 
Such a recognized succession as the consensus of opinion in 
the world has established as marking the Carboniferous System, 
must be a term which includes within its scope the various 
members of the different local series under examination. 
Unequal amounts of sedimentation at different horizons in a 
System and in different districts, have created difficulties, but 
formed an interesting feature in the study of the correlation of 
strata. It has been conceded that in the case of the 14,000 feet 
of strata which constitute the Joggins section in Nova Scotia, 
sedimentation must have been very rapid, and though deposited 
in a perfectly unbroken succession, such strata may have taken 
much less time actually to be laid down than a few hundred feet 
of shales and sandstone belonging to the same system in another 
section. 
1t follows from this, that local series of Carboniferous strata 
may be of very great thickness in one part of the continent, or 
comparatively thin in another part. It is possible for the whole 
system of the Carboniferous to be unusually extensive in its 
development of sediments, as has certainly been the case in Nova 
Scotia when compared with sediments of the same age in Penn- 
sylvania. here is evidence of great rapidity in sedimentation. 
Evidence of rapidity in sedimentation is clearly seen in the 
strata, what I refer to the Eo-Carboniferous of Colchester and 
Pictcu Counties in Nova Scotia, as represented by the Union and 
Riversdale formations. Ripple-marked surfaces and shallow 
water indications occur on all sides. Hundreds of feet of 
unbroken succession of strata, practically each stratum beauti- 
fully marked by ripples and wind action, as well as by the foot- 
