Haupt. ] 24. (Dee. 16, 
OcEAN DYNAMICS. 
The effect of this racing of the waves in search of an escape 
from the pressure of the flood tide is to scour off and prolong 
the sharper lip at the gorge and to flatten out and beat back 
the opposite shore, thus shifting the position of the “inlet” 
until insome instances it is transported considerably to one 
side of the medial line of the inner bay, or entirely closed. 
Thus, the position of the thalweg is made to cross the gorge 
obliquely, and furnishes additional evidence of the resultant 
direction of the external or flood movement. *These movements 
are fully illustrated in the comparative chart herewith sub- 
mitted of Barnegat Inlet (Plate IV), from which it is seen that 
the flood resultant comes in from the north, prolonging and erod- 
ing the northern spit compressing the ebb against the light- 
house shore, from which it has cut away so great a volume as 
to seriously endanger the structure. The total movement in 
about thirty-four (84) years has been half a mile, or about 
eighty (80) feet per year. Had this action been previously recog- 
nized the lighthouse would probably not have been placed in 
so dangerous a position, but on the north spit. During the pre- 
vailing north-east winds of this spring the encroachments have 
been more rapid and extensive than at any previous time. 
The remedy is apparent, but will be stated generally further 
on in this communication. The effort of the ebb is not to 
oppose the flood resultant directly, but to turn away therefrom 
and assume a direction as nearly as may be at right angles 
thereto. 
Thus the flood will roll the sand up the gentler outer slope to 
the crest in a direction normal to the main channel, while the 
ebb will sweep acrossits path on the line of least resistance, 
*This paragraph was interpolated here after the paper was written, See Sup lement. 
paragrap is pp 
