retreated 1.58 kilometers landward by 1886. The glacial headlands of Chatham 

 were exposed to the sea and eioded rapidly. During i year the cliff near 

 Chatham Light eroded 31 meters (Mitchell, 1875). At least one street was lost 

 from the town as waves eroded developed land (Goldsmith, 1972). 



The cycle of inlet formation, dissolution of the southern part of the 

 spit after breaching and migration of the inlet to the south, has occurred 

 three times since explorers first visited Cape Cod. The complete cycle takes 

 between 100 and 175 years. North Beach has not been breached since 1846; a 

 new inlet-spit elongation cycle appears imminent (Onysko, 1978). 



There is no record of inlets north of the 1626 Sparvow-Hawk site, nor is 

 there reason to believe that the initial inlet of the second cycle was formed 

 as far north as the 1626 inlet. The landward migration of North Beach was, 

 therefore, controlled predominantly by overwash processes north of the 1626 

 inlet, where the barrier is backed by an extensive salt marsh or glacial head- 

 lands. All barrier features south of the Spavrou-Hawk site are younger than 

 354 years, having been influenced by inlet dynamics and spit regeneration 

 during this time. 



4. Historic Changes: Quantitative . 



a. Introduction. The entire Nauset Spit system has been constructed by 

 longshore sediment transport from the eroding outwash plains of Eastham, 

 Wellfleet, and Truro, and can be reasonably divided into three major units: 

 Nauset Spits — Eas.:ham and Orleans fronting Nauset Marsh; the section of North 

 Beach north of the 1846 inlet (Old North Beach); and North Beach south of the 

 1846 inlet (New North Beach; Fig. 3). Tine present spit north of Nauset Inlet 

 (2.7 kilometers; Fig. 2) has not been subject to inlet dynamics in recent 

 times. The area between Nauset Inlet and Nauset Heights (1.8 kilometers) has 

 eroded and rebuilt several times in recorded history by inlet migration. Old 

 Ncrth Beach (17.9 kilometers) has not been affected by inlet breaching since 

 1868. The southern 2 kilometers of North Beach developed as a result of 

 southerly migration of the 1626 inlet. New North Beach (6.7 kilometers) has 

 been created since 1846 and does not have remnant salt-marsh peat below 

 surficial features. 



There have been several studies of shoreline changes along the Atlantic 

 coast of Cape Cod. Field surveys of Nauset Spit were conducted by the U.S. 

 Coast Survey during the 19th century. Nauset Spit-Eastham was surveyed in 

 1856 and 1886; Old North Beach was surveyed in 1868 and 1886; and New North 

 Beach was surveyed in 1851 and 1886. Marlndin (1889) compared these surveys 

 to calculate the rate of shoreline erosion along the spit system (Table 40). 

 "T" sheets were published from these data for New North Beach in 1851 and 

 1886, Old North Teach in 1868, and Nauset Spit-Eastham in 1856. The tran- 

 sects surveyed by Marlndin in 1886 along the Nauset Spit-Eastham section were 

 reoccupied in 1957 by Zeigler, et al. (1964), and comparisons were made to 

 earlier surveys (Table 40) . An aerial photography study of shoreline changes 

 was recently conducted along the entire outer Cape (Gatto, 1979). The shore- 

 line position of two locations on each of Nauset Spit-Eastham, Old North 

 Beach, and New North Beach was recorded from a series of photos taken between 

 1938 and 1974. The rate of shoreline erosion at these positions appears in 

 Table 40. 



164 



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