HIDDEN PERILS OF THE DEEP 



825 



. CLd Draught of 



KewYobk. 



CHART OF NEW YORK HARBOR MADE IN 1 737 



each day. During the same period of 73 

 years the western end of Coney Island 

 has moved westward less than 0.2 mile. 



The Haulover is a narrow strip of 

 land on the eastern side of Nantucket 

 Island, separating Nantucket Harbor 

 from the ocean. This was broken through 

 "by the sea in 1896, and after remaining 

 ■open for 12 years, closed again in 1908 

 through natural causes. (See page 831.) 



Much of the change observed along 

 •coasts composed of the softer materials 

 is the cumulative effect of wave and 

 storm action. In some exposed localities 

 channels through shifting materials 

 •change rapidly and frequently ; so that, 

 no matter how accurate the survey, the 

 chart cannot be depended upon to repre- 

 sent the true conditions for more than a 

 short time. At Fire Island Inlet, Long 

 Island, it is reported that the local boat- 



men must take soundings two or three 

 times a week for about nine months of 

 the year, and especially after every blow, 

 in order to keep track of the best channel. 

 On the other hand, the great storm at 

 Galveston on September 8, 1900, did not 

 materially affect the available channel 

 depth of 26 feet into that harbor, al- 

 though the severity of the storm was 

 such as to raise the tide 15 feet above 

 normal, to largely destroy the city, and to 

 cause long breaks in the jetties. This 

 storm cut back the beach 400 to 600 feet 

 in some places and slightly built it out in 

 others, but on the whole had little effect 

 on the charted information. 



FIFTY SQUARE MIEES OF NEW EAND MADE 

 IN 50 YEARS 



Rivers are bearing vast quantities of 

 sediment and depositing these near their 



