196 SEA AND LAND 



inlet, for the reason that tlie sands of tlie island beaches are 

 constantly moving southward, gradually travels in a southerly 

 direction until it abuts against some obstacle. Then the 

 further incursion of sand from the north closes the opening. 

 At some later time, when the streams fiowing into this part of 

 the lagoon are in the state of Hood, and the wind is blowing 

 in a direction to heap up the waters, the closed channel will 

 be replaced by a new opening, which in turn proceeds to 

 travel southward like its predecessor, until in due process of 

 time it also is closed. Thus by watching the direction in 

 which these migrating inlets journey we can ascertain the 

 average direction in which the sands are impelled along the 

 shore. 



Where an inlet remains for a considerable time in one 

 position, the debris which passes through it toward the sea 

 accumulates in the form of an extensive platform on the sea- 

 ward side of the opening. Through this submerged, outward- 

 curving, delta-like accumulation the currents make tortuous 

 channels, generally two or more in number and containing no 

 great depth of water even at high tide. The formation of this 

 curious platform is due in part to the efTect of the current in 

 arresting the coastwise march of the sands, and in part to the 

 force of the str(,'am which sets outwardly through the opening. 

 The strength of the outward-setting current is always stronger 

 than the influx, by the proportion which the excurrent river 

 waters bear to the tide which passes through the inlet twice 

 each day. As soon as the inlet has shifted its position or 

 become closed, the waves and currents proceed to break up 

 this peculiar delta formation and distribute its component 

 sands in an even manner over the neighboring sea bottom. 

 15\' a simple inspection of the soundings on the Coast Survey 



