these aquatic communities were preserved, albeit on a larger 

 scale. The mill ponds may have even served to prevent extinction 

 or extirpation of a few rare aquatics such as Hottonia inf lata 

 and Potamogeton confervoides . 



Now, as the old mill ponds are drained one by one, the 

 return of beaver offers hope of reestablishing these communities 

 in their natural setting, at least in areas where trapping is not 

 permitted and the ponds can be maintained on a semipermanent basis 

 (it takes 20-50 yrs or more for this type community to reach 

 its full development) . The early steps of this process can be 

 observed in Lassiter Swamp where the rare Hottonia can be seen 

 invading new beaver ponds as they are extended upstream. 



The water supply for the pond comes almost entirely through 

 Lassiter Swamp, originating in upland forest and agricultural 

 lands. The system is presently just able to handle existing 

 amounts of sediment input and agricultural runoff. Some additional 

 water comes from small direct tributaries to the pond, from 

 rainfall, the water table, and downslope drainage from adjacent 

 slopes. 



The park is found within the Embayed Section of the 

 Atlantic Coastal Plain, in the Chowan River basin. It is tributary 

 to the Albemarle estuary, the headwaters of which extend some 

 distance up the Chowan River and Bennett's Creek. The exact point 

 at which this stream reaches base level is unknown, but apparently 

 occurs within a mile or two below the Merchants Mill Pond spillway. 

 The mouth of the creek is embayed and lies approximately at sea 

 level. Wind tides from the Albemarle Sound and Chowan River 

 frequently cause reversal of flow in Bennett's Creek, extending 

 nearly to the park boundary. 



The mill pond is impounded in a flat, alluvial swamp bottom- 

 land which is only 2 to 4 ft above sea level. The pond surface is 

 6h ft MSL. Communities in Lassiter Swamp represent the type 

 of swamp forest that would have occurred in the pond area before 

 impoundment. The flat-bottomed swamp averages about h mi wide 

 and is bounded on both sides by steep valley walls, which rise to 

 an elevation of about 30 ft MSL. Above these are flat to very 

 gently rolling upland divides which reach a maximum elevation in 

 the natural area of 39 ft. 



These flat uplands are remnants of the Talbot Terrace, which 

 in this area may have been formed by fluvial or estuarine wave 

 action during the Sangamon. The last stand of the sea high 

 enough to have covered central Gates County occurred at the time 

 of deposition of the Norfolk Formation on the eastern edge of 

 the County. Sea level at that time (about 80,000 - 90,000 yrs 

 ago) reached 45 to 50 ft higher than the present in this area 



92 



