25. Physiographic characterization of natural area: 



Climax communities on fluvial bottomland swamp, steep valley 

 slopes and upland divides surrounding Merchants Mill Pond and in 

 Lassiter Swamp » in the Embayed Section of the Coastal Plain 

 Province of the Atlantic Plain. 



Geological formation: Shallow surface formation on upland 

 divides probably an estuarine deposit corresponding in age to the 

 Norfolk Formation (early Sangamon?); over unnamed Pleistocene 

 deposit corresponding in age to the Windsor Formation; over unnamed 

 Pleistocene deposit corresponding in age to the "Moorings Unit" of 

 the Bacon's Castle Formation; over unnamed Pleistocene (Pliocene?) 

 deposit corresponding in age to the Sedley Formation, over the 

 Miocene Yorktown Formation, 



Geological formation age: Surface formation may correspond 

 to the height of the Sangamon Interglacial, about 80,000 to 90,000 

 yrs ago. Steep slopes are erosional surfaces active from the late 

 Sangamon (perhaps 60,000 to 80,000 yrs ago) to the present. 

 Islands in the mill pond, and slightly elevated flats around the 

 pond and in Lassiter Swamp may contain deposits corresponding to 

 one of the higher stands of the sea between 40,000 and 60,000 

 yrs ago described by Oaks and Dubar (1974). The swamp bottom is 

 an alluvial deposit which is presently aggrading. 



References cited: 



Oaks, R. Q., Jr. and J. R. Dubar. 1974. Post-Miocene stratigraphy: 

 central and southern Atlantic Coastal Plain. Logan, Utah; Utah 

 State University Press. 275 p. 



136 



