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Glynn County: History and Lore: Ed Green Book:
St. Simons History
I. THE ISLAND AND THE INDIANS
In the long ages past, when the planet Earth was in the process of creation, even then, the area of the earth we know as coastal Georgia was an ancient island. The first ancestor of our present island was a land mass which geologists have called "Appalachia". This had nothing to do with the present Appalachian mountains, for this was before their formation. At that time they were at the bottom of a huge continental trough filled with sea water and being ever loaded with land material eroding from both the land masses on the west and the island of Appalachia on the east.
This great primeval island, over 500 million years ago, extended from the present Gulf of Mexico to Maryland, from the present mountains to the east edge of the continental shelf. For 200 million years it remained so, until gradually it elongated to the north end and became attached to the continent. Now as a peninsula the sun rose and set for another 100 million years, until gradually the island became a part of the continent as the mountain ranges were born.
Even as it became part of the continent, the ocean shore line remained in its original position for 50 million years. Then at some early time a melting of the polar glaciers caused the waters of the Atlantic Ocean to invade the land and to cover it to the place which geologists call the Fall Line. This extends across Georgia from Columbus through Macon, Milledgeville, and Augusta. With successive warming and cooling trends of the earth across the ages, this land was successively covered and uncovered by the sea. Deposits of ocean sediment covered the ancient island, so today one would have to drill four or five thousand feet to reach the rock of the original island of Appalachia.
The present coast line was established in the steps of creation during the last ice age, known as the Wisconsin freeze, 25,000 years ago. This Wisconsin freeze and its subsequent thawing was the immediate cause of our present sea islands. As the ice melted and the waters rose, there were at first similar islands to the east with salt marsh on the seaward side of our present islands. As the waters further rose our present land is the top of sedimentary rock stacked in layers on the remains of this the most ancient island; then as the continental glaciers melted, our islands were separated from the mainland.
Of course, this is recent geological history of perhaps only 1000 years ago. Some students of ocean geology believe that another glacial melt began in 1920 and calculate that the rise in Atlantic waters will be 11/2 feet a century. If so, and if the trend continues, in another thousand years one could witness the emergence of areas of the coastal mainland as the new islands of the sea. Of course, the trend could change in the other direction at any time as well.
Before turning to the emergence of man upon these islands, there are three other physical features of which we should be aware.
The first is our source of fresh water. On an island, surrounded by the salt water of the sea and the brackish water of the creeks and rivers, even on a hot, almost rainless summer, how can enough fresh water be drawn for thousands of homes, large industries, watering of lawns and golf courses? Where does so much fresh water come from? The answer is artesian wells. Hundreds of miles away in the mountains, water enters into a stratum of porous rock which outcrops to the surface. This porous rock when underground runs between layers of impervious rock, both below and above, through which little water can escape. It then gradually moves downhill from the mountain and coastal plain through the porous rock until at some lower level it again outcrops as a large spring or until it can be tapped by a drilled well, which is a man made spring. The greatest portion of the water has a rate of movement through the rock of less then ten feet a day, so it would take water two or three hundred years from entering as rain in the mountains until it is tapped for use in the coastal islands. For example, in 1885 a great flowing artesian well was dug at St. Simons Mills by the Dodge, Meigs & Co. lumber mills. It was 437 feet deep with a flow of 200 gallons per minute through a six inch pipe. The water rose in a stand pipe 38 feet above the ground and flowed into a reservoir as high as the top of the mill. This gave aufficient force for fire fighting as well as water for mill work and fresh drinking water. Concern is now arising in the present time a century later, that heavy industrial use and increased population is drawing out the water more rapidly than its flow can replenish; brackish water then creeps in. Therefore, sources of fresh water such as the rivers are being considered in order to conserve from the artesian wells.
The second physical feature of interest is the relative freedom of St. Simons Island and its area from the most destructive force of hurricanes. Although even a small hurricane is too much, the winds over Georgia's coastal islands are much less vicious than at most other places. In the past 200 years there have been only four or five of consequence, and they were small compared to many occurring at places both north and south of here. Only one took many lives: that of 1804 when about 100 Negro slaves crossing the Hampton river in open boats were drowned. In 1898 a large portion of St. Simons Island was flooded by a hurricane wind that heaped up a high rise of water to about five feet above the marshes. It was no surge or wall of water, but a rise from wind sustained tides. The water receded in a very few hours, having chiefly damaged livestock caught on the marshes.
The explanation of St. Simons' relative freedom from hurricanes is related to the Gulf Stream. Brunswick is the mid-point of an arc with Miami on the south and Cape Hatteras on the north. The Gulf Stream somewhat follows the concavity of the shore line. It is closest to land at Palm Beach and Cape Hatteras. It is farthest from the shore opposite St. Simons Island, where it is a distance of 80 miles. Hurricanes breed in the Caribbean and then move into the low atmospheric pressure areas of the heated surfaces of the southern states. Florida is the nearest large land area to their breeding grounds, therefore they bend their course toward the peninsula. They may hurdle across into the Gulf of Mexico, where they may turn north into the Gulf states or head back to Florida and out into the Atlantic. Here they are caught in a mighty trap-the heated area over the 50 mile wide Gulf Stream forms a long corridor of light air between two walls of heavier air. It is along this corridor that the hurricane travels northward. Thus it passes only within 80 miles of St. Simons Island. Since it passes St. Simons Island on its left as it moves northward, St. Simons lies in the less dangerous semi-circle of the hurricane and the winds over Georgia's islands are less vicious than they would be on lands that might lie on the right side in the more dangerous winds.
Also concerning the weather, it should be noted that during the summer the area is under the influence of the Bermuda High, laying off to the east. This prevents the usual progression of Hi and Low pressures from moving through in normal progression. Thus, in summer the weather is subject to local thunderstorms, rather than to the large system of atmospheric movement. Of course this is no longer effective in the hurricane season, and as fall comes near, the pattern of weather movement returns to normal.
Local winds are caused by the differential heating of the air over land and water-the land and sea breezes. Land heats more rapidly than does water by the sun's rays; and similarly the land cools more rapidly with the coming of night or winter. Therefore, in summer the land near the seashore is heated more rapidly than the water. The heated air on land flows upward being lighter, and the cooler heavier air of the sea moves in to fill the place. This is the sea breeze. Also from this we have clouds or thunder clouds almost every summer afternoon as the rising hot air becomes chilled and its moisture is condensed. Usually the breezes blow from the sea to the land from about noon to perhaps one o'clock a.m., when the process is reversed by the sea being by then warmer than the land.
Fogs also spring from a difference in temperature. Just as dew or frost is formed on a still night by radiation of heat from the ground, so is ground fog formed in their stead if the air should be stirred by a very slight breeze. Smoking streams on a cold morning is an example of ground fog. When warm air moves over a colder ground surface, such as wind blowing from a warmer sea to land
on a cold night, there would develop an advection fog. A frontal fog is just a cloud on the ground. Although fogs plague many coastal areas, it is not a severe problem in the St. Simons Island area for there are no extreme differences in temperature between land and sea.
The third noteworthy physical feature is the marsh. Twice a day bathed in sea water with the rising and falling of the tide, it has developed a unique life of its own. Fertile in its production of protein from marsh grasses and marine life, it enriches the ocean water and plays an important part in the food chain of the sea and land as well.