200 Holmes's Notes on the Geology of Charleston. 



" Many years ago I observed a spring, quite small, just at the 

 edge of the highland outside of the edge of the basin : and with 

 the hope of getting an opening for the water, which was so con- 

 veniently situated for use, I removed the thin stratum of clay so 

 as to expose the marl. T found the water issuing from a very 

 small fissure in the marl ; into which I bored with a common 

 carpenter's auger, as deep as the instrument would permit. On 

 withdrawing it, the water spouted up considerably above the 

 surface. I then cut off a portion of my fishing-rod, a large cane, 

 and punched out the joints, so as to make a continuous tube of 

 about six feet. This was inserted in the auger-hole, and luted 

 with clay ; and the water immediately ran out at the top of the 

 tube. This continued for several days, until the frequent remo- 

 val and replacement of the tube made the hole too large to per- 

 mit me to confine the water to the tube. 



M In about a week, or perhaps longer, the opening increased to 

 a foot in diameter, and a rod could be passed down eight or ten 

 feet ; and upon dropping a line into it, with about an ounce of 

 lead, fish of considerable size were often caught. I have no doubt 

 that these fish entered at the opening from the basin. 



"At 'Pooshee,' near Black-Oak, the plantation of Dr. Henry 

 Ravenel, there are several springs of this character, arising imme- 

 diately from the Eocene. 



"At Chelsea Plantation similar springs exist; and in several 

 places in the woods there are small deep holes, containing clear 

 water, called ' Fountains,' which communicate with openings in- 

 to cavities in the Eocene marl. North of Pooshee, in the pine 

 land, there are several of these fountains which communicate ; 

 the streams, like all those I have mentioned, running south, and 

 emptying into a branch which is known as the ' Fountain Swamp.' 

 These fountains are of the same character as the larger limestone 

 sinks, well known through the marl region. They are caused 

 by streams of water running through fissures or cavities in the 

 marl, which gradually wear away the bed, increasing the cavi- 

 ties; the roofs of which are perpetually falling in, until they be- 

 come too thin and weak to sustain the weight of the earth above 

 them. When these streams are near the surface of the marl, 

 small portions of the earth sink in, and fountains are formed. 



When the streams are deeper, lai 



low, before the mass above falls in, when the ordinary lime-sinks 

 are formed : frequently these are quite dry, and many of them 

 remain so after the heaviest rains; the water percolating through 

 the earth, and finding its way to the stream, still existing below. 

 At other times the streams are obstructed by the fallen mass, and 

 deep ponds are formed, which have water at all times. 



" The famous ' Eutaw spring in the field,' is an instance of a 

 fountain formed bv the breaking in of the earth : above one of 



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