STRATIGRAPHIC CONFORMITY AND UNCONFORMITY 207 
ments of the coastal province, resting upon the Cretaceous pene- 
plain, thicken enormously seaward. This has been abundantly 
confirmed by borings for individual members of the coastal plain 
series. Thus the Miocene formation, hardly a hundred feet thick 
near the landward edge of the coastal plain in the vicinity of the 
Delaware River, is more than a thousand feet thick at Atlantic 
City. The idea that sediments are necessarily thickest where they 
are coarsest must be reversed for the coastal province; and we must 
recognize the essentially wedgelike character of the formations of 
this province in directions normal to the coast. 
The upper and lower members of the entire. coastal series are 
strongly, and the upper and lower strata of one and the same mem- 
ber are distinctly, divergent seaward and convergent landward. 
Apparently, then, this sphenoidal tendency may be set down as 
the dominant and specially characteristic structural feature of the 
province; and yet, where subaerial erosion has not intervened, 
conformity prevails throughout; for the successive beds are every- 
where conformable, the cumulative lack of parallelism becoming 
appreciable only when a notable thickness of sediments has been 
traversed. 
TERMINOLOGY OF CONFORMITY 
For the wedgelike type of conformity which we have seen to be 
specially characteristic of the coastal province, sphenoconformity 
appears to be an appropriate name; and for a correlative term, 
applicable wherever the strata are approximately uniform in thick- 
ness and sensibly parallel throughout, or in the general view, plano- 
conformity is suggested. Planoconformity may obtain locally on 
the continental platform, but must be regarded as specially charac- 
teristic of the abyssal ocean floor. 
It is an interesting question as to the effect upon the conformity 
of strata of contemporaneous deformation. If the deformation take 
the form of a general tilting, sphenoconformity. will naturally 
result, as we have seen. And plication, conceding the possibility 
of its surface manifestation, would, apparently, yield only a more 
localized sphenoconformity. Contemporaneous faulting, on the 
other hand, suggests fractoconformity, although it is doubtful if the 
