BROWN — PLANT LIFE OF NORTH CAROLINA LAKES. 327 



consisting of soil particles and vegetable matter, mainly the latter, 

 some of which is deposited at the western end and has enriched that 

 part of the lake. Most of the debris, however, comes from the lake 

 itself and a large part of this is carried by the current to the eastern 

 end. Some debris is washed in from the shore at the sides, or blown 

 by the wind from the interior of the lake to the sides, but the char- 

 acter here has not been changed to nearly the same extent that it has 

 at the ends. Where the debris has been deposited the surface soil has 

 been changed to a soft mud. This change is more pronounced at the 

 ends, especially the eastern. From the ends toward the center the 

 change becomes gradually less pronounced, until in the second fifth 

 of the distance from the western to the eastern the soil is left a coarse 

 sand, which is packed by the waves. The canal across the lake has 

 been filled up with humus. 



The central zone is confined to the sandiest soil in the lake. The 

 soil becomes muddier toward the outer part of this zone until it 

 passes over into the intermediate zone. The soil here, in turn, gets 

 muddier toward the outside until the intermediate gives way to the 

 marginal zone. The marginal and intermediate zones extend around 

 the central, but are widest at the ends and especially the eastern end. 



MARGINAL ZONE. 



The marginal zone is from 1,800 to 2,200 feet wide at the eastern 

 end and about 1,300 feet wide at the western end. At the latter it 

 extends into the lake along the line of the old canal as a narrow 

 tongue for 1,450 feet, and at the former it extends farther along the 

 canals than elsewhere. From the eastern end this zone decreases 

 in width toward the sides until, in the second fifth of the distance 

 from the western to the eastern end, it is about 500 feet wide on the 

 southern side and disappears altogether for a short space on the north- 

 ern side. Except at the narrowest parts, that is, in the second fifth 

 of the distance from the western to the eastern end, this zone extends 

 far out into the deepest water of the lake while it does not extend into 

 the sand of the second fifth even when this is in shallow water. 

 Between and on the sides of the canals at the eastern end where the 

 soil is removed from the current there are rather sandy patches where 

 the vegetation resembles that of the next zone. The principal growth 

 on these patches is Eleockaris mutata and Castalia odorata. 



The roots of the grasses and sedges of the marginal zone are 

 mostly in the surface mud and large clumps can be readily pulled up. 

 But it is not to be supposed that mud is necessary for the growth of 

 all of these plants, as a large number of them are found on the land 

 around the lakes. Here, however, the soil is a gray loam and much 

 softer and better than the coarse packed sand of the lake. 



