352 E. M. KINDLE 



not be checked would indicate that two hundred to two hundred and fifty 

 years must elapse before the whole estuary is carpeted with halophytes.' 



Periodic and cataclysmic variations. — Variations in sedimentation 

 which correlate with a time factor may be referred to two classes: 

 (i) periodic or seasonal, and (2) those without any definite period 

 of recurrence which may be termed cataclysmic. To the first 

 class belong the differences in the quantity of sediment which is 

 deposited on a delta front during the spring flood period and the 

 winter season. Such differences may be recorded in banding or 

 lamination similar to those which Sayles^ has interpreted as of 

 seasonal origin in certain aqueoglacial deposits. To the cataclysmic 

 order of variability belong the profound alterations in coast lines 

 and in shifting of the sediments near them which result from 

 phenomenal tides, great storms, and tidal waves. The Bay of 

 Fundy has furnished a good example of tides of extraordinary 

 height in the Saxby tide, which accompanied the heavy Saxby 

 gale of October 5, 1869.^ The destruction of the city of Galveston 

 a few years ago, resulting from the piling up of sea water on a low 

 shore by a great storm, illustrates well the profoundly destructive 

 character of storms of maximum intensity which may recur only 

 at intervals of one or more centuries. The folklore of many races 

 affords evidences of such phenomenal disturbances in the normal 

 relations of land and sea in the form of legends regarding a uni- 

 versal deluge. 



The rise of the sea to an unusual height resulting from tempests 

 of exceptional violence over low-lying lands which occurs at widely 

 separated intervals along some coasts has frequently resulted in 

 sudden and most comprehensive alterations of the physical geog- 

 raphy. The piling up of the water of the North Sea on the north 

 coast of Holland has repeatedly resulted in submergence and great 

 disaster to extensive areas in Holland within the historical period. 

 It is estimated that 2,336 square miles'* have been swallowed by the 



' F. W. Oliver, "An Experiment in Co-operative Fieldwork in Botany," The 

 Southeastern Naturalist (England, 1907), p. 41. 



^ R. W. Sayles, "Seasonal Deposition in Aqueoglacial Sediments," Mem. Mus. 

 Comp. ZooL, XL VII (1919), 1-63, pis. 1-16. 



3 Robert Chalmers, Can. Geol. Surv. Ann. Rept., Vol. 7, n.s., 1894 (1896). 



^ E. Reclus, The Earth and Its Inhabitants, III, 462. 



