OF SOUTH CAROLINA. 191 
The mouth of the S. Santee presents an interesting illustration of this: a narrow sand bank 
extends into the Atlantic from the north bank of the river, which has been thrown up by the waves. 
This bank has advanced gradually for the last thirty years, at the rate of about one mile in ten 
years, as I was informed by Mr. Lucas, who has watched its progress with great care. 
The breakers first make their appearance at a distance, and gradually push forward the sand, as 
they slowly approach the shore. When the sand rises above the surface and the water becomes 
too shallow to produce breakers, they disappear, and commence again off the shore, and farther 
south. 
In the mean time still water, or even an eddy, is produced on the opposite side of the river, and 
the fine mud brought down by it is deposited, forming, at low water, an immense mud flat. In 
the reduced plan of Murphy’s Present, in the following pages, this flat is represented by the dotted 
line near the shore. 
The portion of the flat next the channel is composed of coarser materials ; between this and the 
land a sort of lagoon channel is left, but which is gradually filling up with light materials, such as 
leaves and other vegetable matter, drifted back by the eddy. The depth of these mud flats is only 
limited by that of the bottom of the river, and hence it is frequently very considerable. When they 
attain the level of high water they are soon covered by the marsh reed, (Spartina glabra.) Their 
progress in rising is now much slower, because they no longer receive accessions from the river or 
tides, excepting on extraordinary occasions. 'The annual crop of reeds, however, produces a grad- 
ual accumulation, and the moment any portion is elevated completely above tide it is taken pos- 
session of by tufts of rushes. 
It is in this manner that the numerous verdant low islands in Charleston Harbor, and along the 
coast, are formed. 
It is observable that on the borders of the channels by which these islands are often separated, 
they are higher than in other parts. This is often indicated by the growth of shrubs, such as the 
Myrtle and Baccharis, upon the elevated spots. A few inches of sand, when they are above tide, 
would fit them for the growth of pines and other trees, and give them all the appearance and char- 
acter of permanent land. 
But it is not even necessary, for the growth of swamp trees, such as the Cypress, (Cupressus dis- 
ticha,) that the land should be elevated above high-water. All that is required to fit them for this 
purpose is the exclusion of salt water. How this takes place will appear farther on. 
I have mentioned that these Islands or flats are protected from the direct action of the ocean 
waves by a barrier of sand thrown up by the ocean itself, consisting of a sandy beach and a series 
of low sand-hills, which are constantly changing their outline, and frequently their position. 
All the conditions necessary for the formation of these moving sand-hills are dry weather and a 
certain breadth of beach. Every breeze carries along with it, when blowing landwards, particles of 
fine sand, till they meet with a log, a bush, or any other obstacle, when they begin to accumulate 
in proportion to the velocity of the wind, and with extraordinary rapidity—piling up and running 
over the top. This is continued, if the wind be strong enough, until they rise to a height of thirty 
or forty feet, which seems to be the greatest height that they attain on the coast of South Carolina. 
They seldom recede from the ocean a distance of more than half a mile. When the beach is 
removed by the encroachment of the ocean, or any other cause occurs to prevent further movement, 
