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. 



It 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. There 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 

 Pictou 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- 



