CHAPTER 1 



ORIGIN AND DEVELOPMENT OF THE MARSHES 



It may seem odd to begin with an 

 observation about rocks, but they were 

 the first things I noticed when I went 

 out across a New England salt marsh. 

 They seemed out of place; marshes were 

 sedimentary environments, not high 

 energy places like sea cliffs or 

 cobble beaches. But my images had 

 been formed in Coastal Plain marshes 

 to the south, where larger supplies of 

 sediment from the rivers developed 

 mineral soils around the grasses and 

 helped to build the marshes outward 

 across accreting shoals. The northern 

 marshes filled with peat were 

 different, and they made some 

 processes that were operating all 

 along the coast more conspicuous. 

 There had been other oddities, like 

 tree stumps, in many marshes I had 

 seen, but for some reason the rocks 

 caught my attention more forcefully. 

 They were a dissonant note--cold, 

 inorganic, gray, and unmoving amidst 

 all that green and windblown grass. 

 It was a useful lesson to see them in 

 the middle of a Spartina meadow, and a 

 reminder of the complexity of marsh 

 development. 



Since the present-day marshes are 

 still responding to the forces that 

 produced them, it is of more than 

 historical or academic interest to 

 investigate marsh developrrient in some 

 detail, particularly with respect to 

 the Northeastern United States. The 

 story of how the rocks came to be 

 there, or rather of how the marsh 

 grass came to grow around the rocks, 

 is an interesting one that began as a 



formal scientific inquiry at least 125 

 years ago. 



EVOLVING CONCEPTS OF MARSH DEVELOPMENT 



Subsidence and Sea Level Rise--the 

 Mudge Model • 



In 1857, B.F. Mudge (1862) 

 presented a paper to the Essex, 

 Connecticut, Institute in which he 

 described his findings from a core 

 taken in the Romney Marsh, near Lynn, 

 Massachusetts, at a site "about one 

 foot above ordinary high water mark 

 and only overflowed by the higher 

 spring tides." The remarkable feature 

 of this core was that it showed the 

 roots and rhizomes of the marsh grass 

 extending down uniformly to a depth 

 well below normal low tide. Because 

 the grasses grew only above the normal 

 high water level, Mudge concluded that 

 the marsh had been subsiding and that 

 the subsidence had been counter- 

 balanced by a upward accretion from 

 grass growth and subsequent sediment 

 deposition. The process responsible 

 for the subsidence of the marsh was 

 not known at that time, and Mudge 

 speculated that it might be due to 

 erosion beneath the marsh caused by a 

 "current of water in the diluvium 

 under the clay. " 



As more cores were examined from 

 many marshes, however, it became clear 

 that Mudge 's findings were too 

 common to be explained by such a 

 local phenomenon (Johnson 1S25). The 



