37 



In Horry and Georgetown counties, it overlies the Pliocene, as has 

 been fully determined ; and if the report of the Special Committee on 

 the artesian well at Charleston is to be relied upon, the Pliocene also 

 underlies the Pleistocene there. From a depth of sixty-five feet were 

 reported shells of the Pliocene Age. It is well known that, following 

 the Pliocene submergence and deposition, there was a period of ele- 

 vation and extensive erosion. Now, it is altogether possible, entirely 

 probable, that the Pliocene was entirely eroded and carried away in 

 places, but it is hardly probable that it would be altogether removed 

 from so extensive a stretch of country as that from southern George- 

 town to the Georgia line, as some have supposed, as may be assumed 

 from the statement made : ''They [the Pleistocene strata] rest in 

 Horry and Georgetown on the Pliocene and for the remainder of the 

 coast on the Eocene." In many places, no doubt, and over extensive 

 areas, they do rest upon the Eocene ; but the fact, if it be a fact, that 

 the Pliocene exists at a depth beneath Charleston that corresponds to 

 the thickness of the Pleistocene is an indication that the Pliocene un- 

 derlies the Pleistocene not only in Horry and Georgetown, but all 

 along the coast where it has not been entirely removed by erosion. 

 For if the Pliocene exists beneath Charleston, as has been determined 

 by materials brought up from wells where a record has been kept, in 

 all probability it also underlies the Pleistocene in many other locali- 

 ties. This supposition, and in the nature of the case, it can be no 

 more than a supposition, can be held to until records from wells 

 either confirm or contradict it. The likelihood is that it will be con- 

 firmed ; for we have some additional proof that there are remnants of 

 other formations between the Eocene and the Pleistocene from Dr. 

 Dall's examination of some fossils found in the "land phosphate" of 

 Ashley River, thought to belong to the Eocene by Holmes and others. 

 Dall has decided, after carefully examining the fossils found in lumps 

 of the "land phosphate" which were picked up on Block Island from 

 the wrecked cargo of a vessel laden with that commodity, that these 

 phosphatized nodules are not of Eocene Age, as generally supposed, 

 but of Miocene Age, nearly related to the Chesapeake Miocene. He 

 found about twenty species of fossils in these nodules of phosphate 

 picked up at Block Island, not one of which was found to be Eocene, 

 but all were well-known later or upper Miocene shells. Hence his 

 conclusion that the phosphatized nodules were of a later formation 

 than the Eocene ; indeed, of the upper Miocene, corresponding to the 

 Chesapeake Miocene, as has just been mentioned. He adds that the 

 phosphatizing took place after the formation of the beds, possibly in 



