296 EDITORIAL 



is understood by quiescence and readjustment may aid in the 

 removal of doubts and objections, since some of these seem to 

 be based on a rather too rigid and literal interpretation of the 

 terms quiescence and readjustment and their synonyms. Like 

 most terms which relate to the mutual relations of the sea and 

 the land, or of the continental platforms and the abysmal basins, 

 the term quiescent has a merely relative meaning. It does not 

 necessarily signify an absence of absolute movement toward the 

 center of the earth, but simply an absence of differential move- 

 ment relative to other portions of the crust. If the whole crust 

 sinks toward the earth's center at an equal rate in all its parts, 

 the relations of the continental platforms and the abysmal basins 

 remain essentially undisturbed and may be said to be quiescent. 

 Such a shrinkage may theoretically reduce the capacities of the 

 ocean basins just as it reduces the whole surface of the sphere,, 

 and this reduction of basin capacity may cause the sea to over- 

 lap the margin of the land in some degree. But this incursion 

 of the sea, would, if appreciable, be justly regarded as only an 

 incident of the quiescent stage. It would indeed be only one of 

 several factors involved in that transgression of the sea which is 

 so characteristic of quiescent stages. It is only when such a 

 common sinking of the crust toward the center develops differen- 

 tial stresses of such magnitude as to require a notable warping, 

 crumpling, or faulting' of the crust that the relations of the con- 

 tinental platforms to the abysmal basins are seriously disturbed 

 and the quiescent stage is replaced by one of readjustment. It 

 is perhaps even necessary to regard such a common centripetal 

 movement during the quiescent period as a necessary antecedent 

 of the period of readjustment, for such a movement is perhaps 

 necessary to develop the differential stresses out of which the 

 readjustment springs. All objections therefore to the doctrine 

 of periodic quiescence which are based upon the conception of 

 the absence of centripetal motion should be set aside as based 

 upon misconception. The only valid theoretical objections are 

 those which apply to the conception of periods of concordant 

 centripetal movement alternating with periods of discordant cen- 



