512 F. P. GULLIVER NANTUCKET SHORELINES 



marked 1898 is made, that the soundings are considerably shallower than 

 those given by the first map in the series (plate 50, figure 5). From the 

 study of this hydrographic survey we see that the form of the tombolo 

 on the ocean side below the first fathom line had changed but very 

 slightly since the break occurred. The great change is seen above 

 the first fathom line on the ocean side, where the two spits were much 

 worn away during the summer of 1897. The opening between the two 

 broken ends of the tombolo was at this time more than a quarter of a 

 mile wide, although the depth at any point between the two spits was 

 not more than 6 feet. It is also seen that the sand blown along from 

 the southeast along the Wauwinet bluff, and from the north along the 

 bluff of Coskata island, was carried through this opening and deposited 

 in a tidal delta on the inside of the tombolo at the head of the harbor. 

 For several years there was but little change in form of the broken tom- 

 bolo or of the offshore and inshore bottoms. 



The fifth drawing shows the conditions in 1901 (plate 50, figure 6). This 

 is a compilation from information given by the U. S. Coast and Geodetic 

 Survey, the engineers of the War Department, various local sources of 

 information, and observations by the writer. It will be seen that by 

 this time a good deal of sand had come from the southeast and was 

 built into the south or Wauwinet spit. Coskata spit had been worn 

 away slightly at the point and broadened farther north. 



Between the summer of 1901 and the summer of 1902 there was a 

 marked northern extension of the Wauwinet spit and a decided cutting 

 back of the Coskata spit (plate 50, figure 7). It was during this time 

 that the great erosion took place on the southern coast of Coskata (see 

 plate 48, figures 2, and plate 49, figure 1). The form of Coskata spit on 

 the drawing marked 1902 is from measurements made by Dr Benjamin 

 Sharp and the writer on August 6, 1902. The form of this spit was 

 changing constantly during this cutting back of the Coskata end of the 

 tombolo. The opening was still nearly a quarter of a mile wide. 



The seventh drawing gives conditions in July, 1903, and is based 

 largely on a survey made under the direction of Captain C. E. Gillette, of 

 the Engineer Corps of the United States Army (plate 50, figure 8). It will 

 be seen by inspection of this drawing that the Wauwinet spit has grown 

 much farther to the northeast, and that it points farther in toward the 

 head of the harbor than it did in previous years. There were many 

 changes observed by the writer in the form of both of these spits during 

 the summer of 1903. At one time in August the northwest point of the 

 Wauwinet spit formed an island, the waves having broken through at 

 the narrowest point of the spit, about one-sixth of a mile from the end. 

 This was again closed and again broken open later in the summer. The 



