24 HARPER 



Topography and Drainage. 



The topography of the region under consideration is typically 

 "rolling," and quite pleasing to the eye, in comparison with the 

 flatness which characterizes most pine-barren regions. But 

 there are no jagged outlines, or even steep-sided gullies or ravines 

 as in the older parts of the coastal plain. The ridges rarely 

 culminate in peaks, and the valleys rarely if ever terminate in 

 ponds or depressions. A straight line drawn across the country 

 in any direction (of which the railroads furnish numerous ex- 

 cellent examples) , would cross on an average two or three valleys 

 to the mile, each perhaps 20 or 30 feet lower than the intervening 

 ridges. In some places the county is quite flat for several 

 square miles, as may be seen around Collins in Tattnall County, 

 also in the eastern edge of Irwin County near the sources of the 

 Satilla River, and more commonly toward the coastward edge of 

 our territory. Such flat areas seem to be always plateaus, and 

 never valleys, showing that the topography is comparatively 

 young, as we should expect. 



Ponds are pretty well distributed over the whole region, es- 

 pecially in the flat spots, but they are entirely wanting over 

 hundreds of square miles, particularly in the northernmost 

 counties. As has been noted elsewhere,' none of the ordinary 

 ponds are deep enough to retain water throughout the year, 

 and strictly aquatic plants are therefore absent from them. 

 The cause of these numerous ponds is not definitely known. 

 The presence of similar depressions in other parts of the coastal 

 plain is often directly traceable to underlying limestone, but the 

 Altamaha Grit region is singularly free from anything of this kind. 

 There are in the region a very few examples (I have seen one near 

 Douglas and heard of another near Statesboro) of "bottomless" 

 ponds, or "lime-sinks" as the natives call them, but they have 

 little in common with the genuine lime-sinks near the Flint River. 

 At the one near Douglas there is nothing in the color of the water 

 or in the nature of the vegetation around its edges to indicate the 

 presence of any calcium carbonate. 



In the typical rolling country every little valley contains a 



1 Bull. Torrey Club 32: 146. 1905. 



